Hard choices: Considering CPU Overclocking

Some overclocking, yesterday.
When the artist previously known as Fingers McMeer – and my former PC Format paymaster from the good old days – first mooted some contributions to RPS on the matter of hardware, I was struck by a single, sobering thought. For the love of science, please don’t make me talk about overclocking. Here we are, then, talking about overclocking.

And you know what? It’s OK. Because what we’re going to tackle is real-world and worthwhile overclocking. Not the futile, fanboyish sort. In fact, when it comes to CPUs, it’s the sort of overclocking you really ought to be doing if you’re not already. Here’s why.

The background to all this comes in two parts. How the market as a whole got to where it is today, on the one hand, and how I came to own a pathological antagonism to a certain sort of overclocking twaddle, on the other.

Please make it stop.

The latter is easy enough to explain. I’ve simply sat through 27 too many pointless press events involving some hired lunatic hand, for some reason usually Scandinavian, demonstrating the latest chip running at a hitherto unprecedented and entirely irrelevant speed courtesy of liquid nitrogen.

It’s these very same people who buy £500 video cards, but don’t play games. Ghastly. Anyway, more important is understanding the currently patchy-going-on-parlous state of CPU overclocking.

As ever, much of it comes down to Intel, both for better and worse. The problem is Intel’s domination. Its chips are so much better than AMDs, it can get away with what amounts to antagonist behaviour towards its customers.

That means arbitrarily locking out features. Critically in this context, that includes access to the CPU multiplier. And it’s multiplier access you need these days to do any meaningful overclocking.

It’s actually a little more complicated than that. The most popular method of overclocking Intel chips used to be via the front side bus or base clock. This wasn’t a fully pain-free a method, but it did mean most chips in recent years could pony up pretty healthy overclocks, with 1GHz of extra frequency often a reasonable expectation.

And then came the Sandy Bridge generation of chips (which includes the RPS-favourite Intel Core i5-2500K) and the party was over. In simple terms, Intel shifted the clock generator from controlling just the CPU part of the chip to the whole shebang, including features that used be on the motherboard, like the PCI Express interface.

A rare overclockable chip from the evil empire.

The upshot of which is that Sandy Bridge processors and their Ivy Bridge successors fall over if you push the baseclock more that a couple of percentage points from stock. Which means the only option is the multiplier. And that’s something to which Intel chooses to ration access.

K Series and Extreme Edition chips are effectively fully unlocked while some mid range chips have very limited access to overclocking, typically what Intel describes as one “speed bin” or 200MHz to 300MHz depending on the chip in question. Some at the bottom have none at all.

You’ll also need to bear in mind that only certain Intel chipsets give you proper access to the multiplier. So, you’ll need to research that. If in doubt, buy a chipset with a Z or X in the title and you’ll be OK. It’s also true that overclocking mileage does vary between boards. It’s not often a dramatic difference, but the info is out there and easily accessible if you care enough.

With all that in mind, let’s assume you’ve got or are planning on buying a K Series model (if you haven’t, there’s not much to discuss – we’ll come to AMD chips momentarily). What should you be aiming to achieve and how should you go about it?

Well, you’ve got three options. Quick and dirty, which is frankly all the overclocking most people need and all I can personally be bothered with. Next is to use the motherboard’s auto overclocking options for a little help. Finally, it’s the full-on hand-tuned option.

The latter gives the best results, but is monumentally tedious and a classic example of diminishing returns. Don’t bother. Instead, keep it simple and start by jumping into the BIOS and whacking the thing up 500MHz. Then reboot and then repeat, but in 100MHz increments from there until falls over.

Are you afraid of the big, bad BIOS?

Now that the baseclock is a nice, even 100MHz, you do this by knocking up the multiplier one notch at a time (or five notches for that initial 500MHz fling). Precise methods vary, but typically involve flicking a blanket override switch in a branded overclocking menu from ‘auto’ to ‘manual’ to expose the multiplier settings. Google is your friend here, as I hope the comments below will be, too – let’s help each other out. Don’t worry about anything else. Odds are, you’ll get close to or maybe even better than a GHz’s worth of overclocking.

Once you’ve found a stable overclock, my view is that you should knock it back 200MHz and leave it like that forever. Gaming is pretty stressful on PCs, so you want a little margin in hand. But once you’re there, don’t worry about the temps or the power consumption. Life is too short. The odds of killing the chip as described are very remote indeed and the impact on your electricity bill is going to be slim to none.

The only other thing to think about and only if you’re really going for a big overclock is to use your board’s auto overclocking capability to help with voltages. Now, it’s often the case this happens automatically anyway – ie your board will automatically tweak voltages as you go along.

However, if you’re not sure, one option is to enable the full overclocking function that includes allowing the motherboard to do the lot including set the multiplier. The overall results will be mediocre, but the fringe benefit is the CPU voltage the board has come up with. It won’t be perfect for higher clocks, but it will be better than leaving it stock. Note it, put things back to manual and then plug in the new value.

And that really is it. Don’t bother with tweaking the memory, modern chips are bandwidth saturated, or any of the other voltage settings. It’s just not worth the bother.

It’s one big overclocking party over at AMD

If you’re wondering about AMD chips, most of the above applies. The difference is that as the underdog, AMD uses unlocking as a sweetener to tip the balance in its favour. So you’ll find all manner of unlocked AMD chips along with fewer, if any, motherboard restrictions.

Indeed, as this price list shows, every single retail example of the AMD FX processor is a Black Edition and thus unlocked. Just bear in mind that overclocking mileage varies a bit more from model to model with AMD chips. You’re not going to get an extra gig out many FX chips. Well, not unless they’ve really improved things since last I had a play with a hand-picked sample.

Oh, and before I forget, cooling. This isn’t absolutely critical, but you can get a really nice air cooler for just £30 or so. Personally, I think it’s a a worthwhile punt as you’ll be able to reuse it for multiple systems.

Go for anything from a decent brand like Enermax or Corsair with a 120mm. Job done. For those who need hand holding, buy this one. I recently spent a weekend with 12 coolers. One of the worst weekends of my life, if you must know. And then I ended up writing up half of them on holiday in France. All somewhat self inflicted. But I digress. That was the best of the bunch.

The Enermax cooler. Think not. Just buy.

Meanwhile, do not buy one without a fan thinking the silence will be golden. It’s not suitable for gaming. You won’t kill your rig, but you will find the CPU thermal throttles. Not good.

As for water cooling, it won’t buy you much additional frequency for the sort of overclocking we’re talking about and it costs a lot more. It does reduce temps, but honestly, so what? If your cooler’s seated correctly and you’re not running the thing on the ragged edge, because I’ve already told you not to, you’ll be just fine. That said, and to flatly contradict myself, if you’ve money to burn, the latest water coolers are utterly painless, zero maintenance things, so I wouldn’t blame you.

So there you have it. Overclocking ain’t what it used to be, sadly. You can no longer buy a poverty chip and clock it up to flagship speeds. But if you do have a K Series Intel chip, you’d be bonkers not to ramp it up at least 500MHz or so. There really is no downside. A £30 quid cooler and all of a few minutes in the BIOS for free performance and no downsides. Like Arnie said, do it. Do it now.


  1. JohnP says:

    It so happens I did this for the first time last night on my shiny new computer, using link to reddit.com as a guide. Was really quite easy, as you say no point not doing it if you’ve got a K chip and a decent cooler. (I’ve used the Hyper 212 EVO.)

  2. Scandalous_J says:

    My friends maintain a ridiculous paranoia regarding overclocking, I thank you for this.

    • alundra says:

      I woudln’t advise to OC on a passive heatsink, but if you know what you are doing, yeah, there are dozens of better performing alternatives, and quieter to, to the enermax t40

      link to legitreviews.com

    • Savagetech says:

      Just saying what? That you can pull somewhat acceptable temperatures running the CPU at stock speed? They got 78.25°C running that i7 2600K without fans which is only 20°C below the max temperature, while Intel recommends a temperature of 65°C. If that system was overclocked or used at full capacity (e.g. gaming) for any appreciable length of time, that cooler just wouldn’t cut it. As far as their temperatures with active cooling: why buy a silent CPU cooler if you’re going to run several more fans anyway? Unless you’ve designed your PC from the ground up with silent components, you’re going to have fans in your power supply, GPU, and case.

      I guess I don’t get what you’re trying to say here. Yes, you can use passive coolers and not melt your system. No, you won’t want to use passive cooling when overclocking (the subject of this article) or gaming (the subject of this website).

  3. trjp says:

    I have to admit that my perception of people who overclock stuff is that they’re far more interested in the raw numbers and “how much they can gain” than they are in the real world differences they achieve.

    I’ve dabbled with it before and I’ve seen interesting increases. In one case I managed to get around 20% improvement in GPU and CPU performance from a budget system I’d built – I was chuffed.

    Unfortunately, the real-world effect of that apparently impressive increase was inperceptible to the human eye – I was getting maybe 2-3 fps more (no-one would notice – no-one would care) and ultimately, I ran the the hardware into the ground a lot quicker than it would have died otherwise I suspect (that CPU and GPU remain the only ones I’ve ever had which died within 2 years of being bought).

    It’s all great stuff but I think it’s worth stepping-back sometimes and realising that all the effort may produce an interesting increase on paper – but it’s unlikely to make a massive difference to actually PLAYING anything.

    Still – we do love to tinker eh? :)

    • Veritaas says:

      You want to see a difference? Play a CPU bound game.

      Seriously. Play Natural Selection 2 or Planetside 2 with your CPU at the default clock, then bump it up by ~30% (3.2->4.3). I get a whopping 15 fps difference in those games, which is important as the fps already averages around 50.

      • trjp says:

        Obviously if it works, it’s cool – I’m just saying that typically, I’ve not really seen massive benefits from it.

        A lot will depend on your hardware of course – a lot of overclocking focusses on taking mid-range (still decent) kit and making it better – wheras I’ve tended to take low-end (cheap) kit and tried to get SOMETHING out of it :)

        • DrGonzo says:

          Then you were overclocking for no reason. If the cpu can handle everything you are throwing at it there is no point in overclocking.

      • zaphod42 says:


        Half of games right now are far, far more GPU bound. Those games will see very, very little increases from overclocking, since your CPU isn’t the bottleneck anyways. Those games you need to buy a new GPU to see better performance. Most Unreal engine games are GPU bond, and in fact most games these days are.

        However, while thats how it was for a long time, we’re getting back to some games being CPU bound.

        Games like GTA4, BF3, Skyrim, Planetside, Crysis 2, and anything on the Source Engine (TF2, CS, DOTA, etc.) Are MASSIVELY CPU bound. These games almost don’t even care what video card you have, as long as its dx9 or better.

        I’ve run Skyrim on HIGH settings 1920×1080 with a 9800GT and a 450, and got very playable frame rates on both. Those are old cards, one is ancient and the other is midrange, and yet I got very, very playable results, because Skyrim is FAR more CPU bound.

      • Stromko says:

        Those (PS2 and NS2) are some of the few games that make me glad that I upgraded my CPU, as little else has benefited .. but the difference is night and day, especially with the former. I had a 2.8 ghz dual-core AMD chip, and went up to a 3.6 ghz quad-core, with everything else on the system staying the same.

        Went from being unable to play Planetside 2 (it would feel like10 FPS outside of the fight and be unresponsive at 1 – 5 once I approached a battle), to it playing just fine. Natural Selection 2 was already playable but I was pretty much fighting by ESP since it dropped so many frames when the action kicked off, and now it’s quite smooth.

        But now I don’t want to overclock, at least right now. Everything’s running fine and I don’t want to shorten the lifespan of the system. The only thing that would tempt me is massive fortresses in Dwarf Fortress and I haven’t gotten stuck in with that in months. Any clock speed increase would be a bit wasted on that until I learn how to make affinities in Windows 7 work properly so that I can give DF its own dedicated core, anyway.

      • Premium User Badge

        Phasma Felis says:

        “I get a whopping 15 fps difference in those games, which is important as the fps already averages around 50.”

        When did we all start pretending that 50FPS is bad? Did I miss a memo? At least 95% of all humans will detect no difference betweeen 50 and 65.

        • MD says:

          80% of statistics quoted in internet comment threads are made up on the spot, to add weight to a personal opinion. When preceded by the phrase “Did I miss a memo?”, that figure rises to a whopping 95%.

          • PopeJamal says:

            The point still remains: I can’t think of a single situation where 50fps on any game would be considered “unplayable” by most gamers.

          • MD says:

            Nobody said that 50fps is considered unplayable by most people though. This was about a 15fps difference, from an average of 50, supposedly being unnoticeable for almost everyone.

            I would certainly consider an average of 50fps (so, depending on the game, you’ll probably be dropping to about 30 quite frequently? I’m not sure exactly, but presumably something like that) to be a noticeably shit framerate in any FPS. Bumping that up to 65 would be a non-trivial improvement.

            As for ‘unplayable’ — I haven’t played NS2 or Planetside 2, but in the multiplayer FPS games I do play (fast-paced deathmatch games in the Quake family, basically), very many people would consider a 50fps average to be unplayable.

            That’s a term with as many definitions as there are gamers, of course, but in this case I’m not just talking about the super-serious hardcore crowd. I’m sure some people would put up with it, but I’m not sure that I could, and I’m far from being the fussiest.

        • Unit327 says:

          I can notice the difference. Also if the game averages 50fps, it’s going to dip to 30 in spots, where it will really make a difference..

    • Turin Turambar says:

      You were gpu-bound, then. Which is the normal thing in games if you don’t have a expensive modern GPU, in the other hand.

    • battles_atlas says:

      Saints Row Third actually breaks due to overclocking, at least on some systems. The audio desyncs from the visuals during cutscenes. As luck would have it it was the first game I played on my new oc’d i5-3570k when I bought it last month

      • Desmolas says:

        Ive had problems with software overclocking before. It seems to cause all sorts of problems for drivers ive noticed. However, if its hardware overclocked (at the mobo and bios level) then it shouldn’t matter.

        However, some games and drivers are just crap and fall over as soon as you even change your Windows background theme. Yes, ive had a audio driver before that was crashing because it expected to see Windows XP’s default theme. Not kidding.

  4. Zanchito says:

    Down to earth advice on a topic I used to be into. Pretty much agree on everything! Also, there are some very quiet air coolers nowadays, for those who like silent environments. Most of my computer noise comes from the graphics card, you need a special solution for that if it bothers you (either one of those with special silent solutions or an aftermarket one, which to me is usually too much hassle for what you get).

  5. MrMud says:

    To find out if your overclock is stable you want to tax your CPU to the max. I would suggest running an application such as prime95 in torture mode for an extended period of time (say 20-30 min). If it doesn’t restart you have probably safe.

  6. plsgodontvisitheforums says:

    Gotta love those hardware articles on rps, good times.

    Leaving everything on auto and whacking on +1Ghz is a good way to put 1.5v through your new shiney ivy bridge calculating square. Don’t do that.

  7. Simon Hawthorne says:

    The link to the Enermax cooler takes me here link to rockpapershotgun.com for some reason, is it broken?

    Correct link is link to techradar.com

    • povu says:

      That game is so cool that it cools your CPU.

    • hamburger_cheesedoodle says:

      “Just in case that hasn’t quite got your attention the fan blade edges have a chrome strip applied to them.”

      Thank goodness! Just what I was looking for in a CPU fan.

  8. mzlapq says:

    I’m considering buying a new computer. how much will I gain by overclocking?
    Overclocking means buying a Z77 motherboard + 3570K) instead of H77 + 3470/50 (less than 10% of frequencies between 3570 and 3450, more than 10% price, from what I see). Z77 from H77 means 30-40% higher price.

    • Zanchito says:

      I’d not pay more than an additional 20% for overclocking if money is a concern, but that’s just me.

  9. Premium User Badge

    wsjudd says:

    Is it just me or is the ‘buy this one’ link going somewhere a bit random? Looks like the http:// was missed off :) The link is:

    link to rockpapershotgun.com

    And the landing page is:

    link to rockpapershotgun.com

  10. Mayjori says:

    I love overclocking, I’ve had my I7 920 running at 4000Mhz for about 2 years now with no issues, on air cooling (third party cooler). Did the quick and dirty method through this guide link to overclock.net

    • Desmolas says:

      i7 920 here. Used same guide! =D Got 3.6Ghz. Was sure i was doing something wrong as everybody else was hitting 4ghz+ and i had a good air cooler. Alas, i think i have one of the handicapped 920’s. :(

  11. Deano2099 says:

    I’ve always been paranoid about overclocking, but have one of the old Intel i7 chips that were supposedly really easy to OC, so after a couple of years thought I’d give it a go. Read through a bunch of guides and it said to start with 1.1v and go to a maximum of 1.25v for longevity and so on.

    Anyways, I’d built the PC myself and had been letting the motherboard do all that, with voltage set to Auto. Turns out that while I’d been doing that, whenever the CPU was under load, the motherboard was opting to stick 1.7-1.8v though it. Ended up manually locking it at 1.2 and had a processor running 40% faster and cooler to boot.

  12. PoulWrist says:

    For games, overclocking is really 99% waste of time, money and electricity. The power of a mainstream CPU today, like a i5 3570, is PLENTY to drive any and all games at 1920x1x00, and that’s when GPU limiting starts to set in… unless you are one of “those people” who run everything overclocked to reach 200 fps because “you can feel the difference”, which I’ve no doubt is probably possible.

    Some people I know say it’s madness to buy such a CPU and not OC it. I say it’s madness to buy such a CPU and do. Nothing is gained. Recently, someone linked me a test where they ran a latest generation midrange Core 2 Quad through a bunch of benchmarks with games, 30 or so titles. First run at stock, second run at 1ghz above stock. The net difference in frames, across ALL titles, wasn’t even 5 fps. So, a full gigaherz extra clockspeed, on a non-top-of-the-line CPU, meaning this is where you should be able to measure differences, if any, and the gain in performance was less than 5 frames per second across 30 different games. That means most these games showed no gain, at all. And if they did, it was tiny.

    Not at home so can’t dig out the link, but it just showed yet again that there’s no point in running your CPU OC’d unless you’re doing something that benefits from it. I’ve seen WoW benchmarking respond very favorably to higher clocks, especially on RAM, which was odd since RAM speed has been shown to be almost nonsensical to everything else… but MMOs in particular seem to like more CPU power. Pretty much all other games do just fine with a mediocre CPU, just slap a big GPU in there instead.

    • Buemba says:

      Agreed. I kept my i5 2500k overclocked for about 6 months or so, went back to stock speeds recently and honestly can’t tell the difference at all even in CPU intensive games like Civ 5. At least when I overclocked my 670 I saw a perceptible improvement in some games…

      Maybe when the next gen of consoles hit games will once again become more demanding and there’ll be a reason to OC my processor, but for now I feel it’s a waste of power.

    • Sakkura says:

      A core i5-3570 is plenty for every game out there today at stock clocks. But it won’t be in a year or two or three. That is when overclocking comes into the picture. It allows you to play more games with perhaps an upgraded graphics card, and still get great framerates with the same old CPU.

    • fish99 says:

      Not everyone has an i5 3570.

    • Fierce says:

      I would say PoulWrist that the general appeal of overclocking, coming from one who has done it oneself, is to save money by opting into a low risk/high return transaction.

      While fine-tuning multipliers, voltages and base clocks in order to achieve the most energy efficient overclock is by definition an enthusiast level activity, one simply being interested in technology enough in order to read previews or reviews of Intels or AMDs newest architectures is able to tell that CPUs have only recently tried their best to overclock themselves using technologies like Turbo bins or Multicore Enhancements. Before Sandy Bridge, the CPU status quo was for a processor to be released that was clocked to never maximize its potential, never reach moderate thermals, and therefore survive for its longevity-minded warranty. Overclocking was merely the only way to receive a “true” upgrade and break free of the typical Tick Tock cadence that focused on new architectures over higher clock speeds; an evolutionary approach to improvement over a pragmatic “step on the gas!” clock speed improvement.

      A very common example is the Bloomfield i7 920, a CPU I think that is going to be remembered for its sheer value, especially the d0 stepping. Selling for under $300 (a feat only recently enjoyed by Sandy Bridge CPUs today), the 920 d0 was clocked at 2.66 but would easily hit 4.00 at very low voltages with a 3rd party HSF. To buy one of these and not overclock it would frankly make the buyer a chump.

      Many people who own one (and I know a few through forums) have to this day no reason whatsoever to upgrade to even todays Ivy Bridge, and they’ve been enjoying that power per watt value for the past 4 years and are well on the way to 5. While it can be argued until the end of time whether there’s a subjective “difference” that can be “felt” or “noticed”, the fact remains that overclocking speaks to the PC enthusiast the same way building a PC from scratch spoke to them in the first place. Both are done for enjoyment, to learn more about the engine that drives their machine, and to save money. 4.0GHz for the price of 2.66GHz can’t go wrong.

      And as soon as that game, application, crowd-sourcing project or whatever comes out that does use that extra power? Those who don’t overclock are definitely going to feel the pangs of obsolescence far earlier than those who do. For no “reason” except for fear and/or ignorance.

    • mashakos says:

      I think it’s a shame that so many people spend tons of cash on gaming PC’s only to use them as glorified consoles…
      Overclocking makes a HUGE impact if you want to run exotic stuff on PC, such as wii/ps2 emulators or extremely taxing engine overhauls for games like GTA 4 and Skyrim.
      In addition to that, overclocking keeps an older cpu more relevant:

      After overclocking my old E8400 to 4.25GHz I could run Crysis at 1080p very high settings using an amd 5870. The cpu was also able to run any game I threw at it on the highest settings right up till last year. I switched to a newer cpu only because I was interested in upgrading to 16GB ram for other purposes. Up to that point though, my trusty E8400 cpu was running like a champ. I was pleasantly surprised to find that my combination of a dual core E8400 and a gtx580 was enough to run GTA 4 ENBSeries at 1080p with a stable 50fps. The only issue I faced was the texture pop-in due to the slower DDR2 memory on my motherboard.
      If you haven’t noticed: I was running pretty much the most demanding game mod on PC using a dual core cpu and DDR2 memory. DDR2!

      A mid-range cpu costing only $200 in 2008, lasting almost 4 years and never losing the top spot in running high end games and apps? The best investment I’d made in a CPU in more than a decade, all thanks to overclocking.

      • Sigh says:


        >>>>>I think it’s a shame that so many people spend tons of cash on gaming PC’s only to use them as glorified consoles…>>>>>

        >>>>>>Overclocking makes a HUGE impact if you want to run exotic stuff on PC, such as wii/ps2 emulators>>>>>

        ‘Nuff said.

        • mashakos says:

          Don’t get me wrong, I love console games. I just prefer the more interesting experience created by a mixture of advanced hardware and programming ingenuity that is found in mods and emulators i.e the ‘PC’ experience.

          This is opposed to the console experience: buying a ‘game’ box, then buying more boxes with little discs in them from Big Publishers that are pretty much not dissimiliar from each other.

        • PopeJamal says:


  13. AbyssUK says:

    Overclocking isn’t fun anymore :( This article proves it.. not even people who know how to do it and the benefits its brings can be bothered to do it anymore…

  14. lizzardborn says:

    Well for all that say overclocking is madness – Noctua D14 can keep ancient i5-750 at 4.1 GHz which effectively allowed me to skip a full upgrade cycle for MB/CPU.

    But you should have mentioned testing of the clock – usually 10-15 minutes of Intel Burn Test are enough to ensure stability.

  15. whatisvalis says:

    I just built a new i5 Ivy rig, and OCing the thing wasn’t particularly fun. They are great chips, but mine turns into an absolute Voltage monger at 4.4, and temps jump 10 degrees. Absolute luck of the draw on what sort of chip you get, but the performance gains over my Q6600 are great. I ended-up using the voltage offset method to OC mine.

    I would not recommend using auto setting for voltage, especially if you have energy saving settings turned off in the bios.

  16. TechnicalBen says:

    Did great with my Pheni II 720 Black from AMD. I unlocked an extra core (yes, really :D) and upped it from 2.8Ghz to 3.2Ghz. I know that’s not much, but I cannot be bothered to fiddle too much with the frequency, and I think 3.4 is the max I can run it at without overheating on with the current heatsink.

  17. paddymaxson says:

    Overclocking i k chips is a breeze, it really is. my i7 is sitting at 4.6 Ghz and I’m fairly sure I could take it higher if I even thought I needed to.

    Edit: By the way, the link to the enermax cooler review is maelformed.

  18. Lone Gunman says:

    Great timing with this article since I was about to attempt to overclock my Q6600 :)

    Even though I don’t have the money/knowledge to try all this extreme overclocking I understand why people do it.

    • Malibu Stacey says:

      Q6600’s are ridiculously easy to overclock. I’ve had mine running at 3 GHz instead of the stock 2.4 GHz since I got it more than 4 years ago with no issues. It’s plugged into a DFI LanParty DK X48-T2RS though and has a Zalman CNPS9700 sitting on top of it which probably has a lot to do with how stable the whole thing is. Average temps are 30-40 degrees per core idle & 70-80 degrees per core at max load (that’s running Prime95 on all 4 cores for 10 minutes or more, in games it’s somewhere between the 2 since no games run on all 4 cores plus the GPU simultaneously as yet).
      As Jeremy says in the article, make sure you’ve a decent cooler on it & you’re good to go as long as your motherboard manufacturer doesn’t hate you.

  19. mr.black says:

    Apart from everything said, my experience has taught me NOT TO DO IT if there’s not enough power. For overclocking, solid power unit is foundation, even more important than usual!

    • Sakkura says:

      Just as important is the number and quality of VRMs on the motherboard. They are effectively the PSU for the components directly supplied by the motherboard, including the CPU.

  20. Soylent says:

    Last year, Microsoft had created a research paper from crash data collected from 1 million PCs. One of the most common causes are overclocked CPU’s. In fact, they say that underclocked CPU’s are the most reliable.

    Among our many results, we find that CPU fault rates are correlated with the number of cycles executed, underclocked machines are significantly more reliable than machines running at their rated speed, and laptops are more reliable than desktops

    The section about overclocking (section 5.1), they even say that after a crash from overclocking, it will continue crashing even if you stop overclocking it.

    The table shows that CPUs from Vendor A are nearly 20x as likely to crash a machine during the 8 month observation period when they are overclocked, and CPUs from Vendor B are over 4x as likely.
    After a failure occurs, all machines, irrespective of CPU vendor or overclocking, are significantly more likely to crash from additional machine check exceptions.”

    Link to the (very) detailed research paper here:
    Cycles, Cells and Platters: An Empirical Analysis of Hardware Failures on a Million Consumer PCs

    In my own experience, I have to agree with this paper. I find that my personal gaming computer crashes more frequently than a family member’s non-gaming computer. Also, for example, my work computers rarely ever crash.
    Other people’s computers crash due to a virus or hard drive failure. My personal computers tend to crash for every other reason (and they are different kinds of crashing- hard lockups or boot failure).

    I guess that’s the price we pay for that extra 10%-20% performance :D

    • mashakos says:

      Crashes even after a cpu is returned to stock speeds? Sounds like permanent damage due to overvolting.

      Overclocking isn’t the tea-leaf reading, shaman practice it used to be in the Pentium Pro days. If you do the proper research you will find a consistent collection of best practices, comprehensive testing methodologies and various methods to avoid instability.

      Case in point: my old dual core was running for more than 3 years without a single BSOD or lockup after a stable overclock was reached. Likewise, my current core i7 3930K has been running on standby since I’ve overclocked it to 4.5Ghz (up time in the task manager is roughly above 180 days).

      It all depends on how stable the overclock you’ve achieved is (really boils down to how much you know about overclocking and how experienced you are) in addition to the kind of apps you run. In some cases even a pedestrian app like firefox will crash eventually after a few months of being kept running and hogging 3 Gigabytes of available memory.

    • emertonom says:

      The section about overclocking (section 5.1), they even say that after a crash from overclocking, it will continue crashing even if you stop overclocking it.

      They don’t say that. They’re repeating the result they described in the opening paragraph of the abstract of the paper–hardware errors tend to be recurrent. A machine with no history of hardware errors had about a 1 in 190 chance of having a hardware error; a machine which _had_ previously displayed a hardware error had about a 1 in 3.3 chance of having another. It does not imply anything about how the system performs if you stop overclocking it; there’s no implication that they got any data about that from this study. Only 2% of the computers they observed were overclocked in the first place; it’s likely that they didn’t observe anyone actively fiddling with the overclock.

  21. grundus says:

    I’ve been contemplating this for ages but am too lazy to seek a guide, I thank you. I’m hoping I can squeeze an extra few frames per second out of Arma II when it goes through a frame rate dip because the lowest it goes in normal play is about 18fps, I only really start to notice the stutter at about 22fps from what I’ve noticed. I assume the dips are due to data being read (because most of the time it happens is when I’m moving long distances) so running the game on an SSD with an extra few hundred MHz (got a 2500K, 4GHz should be trivial from what I’ve heard) will hopefully stop the worst of it… Maybe.

    Can we please, please, please get a Hard Choices covering headsets and/or speakers? That’s a total grey area for a lot of people, I think. Forgive me if there has already been one, I’m lacking coffee and I’m probably about 20 minutes from death.

    • Stromko says:

      I could certainly use advice about head-mounted audio. I prefer it overwhelmingly to speakers (why noise pollute?), but prices can vary by a ridiculous degree despite what seem to be identical features. Finding a surround-sound headset that actually works can also be a hassle.

      Right now I have a Logitech G-35. Right away the issue I had was that it has a USB connection, making it easy to configure but also meaning my dedicated high-spec audio card was worthless and there was suddenly a lot more load on my CPU. A lot of games don’t really support surround sound anyway, and the increased CPU strain was quite appreciable in the titles that supported it. Despite all that, it was overall an improvement to my experience compared to other headphones, but it highlights the potential pitfalls even with a good pair of headphones.

      Now it’s many years later and the cups are getting worn out, I’ve no idea how much more everyday abuse these things can take before there’s actual problems with the audio, and I’ve still no idea if there’s anything better or as-good out there to spend my money on. I also don’t know if it’s possible and worthwhile to find a pair of good surround-sound headphones that will benefit from a dedicated sound-card, if those are even a prospect anymore.

  22. Victuz says:

    I’d love to overclock my processor, I swear. It’s the bottleneck of my system.

    the problem is…if I overclock it even a tiny bit I suddenly don’t have enough electricity to run the whole system!
    Crazy I know! My power unit is busted I need to buy a new one :p.

    • sibane says:

      If you’ve got an old power supply, no point in overclocking. Those things lose power over time, and an old PSU that would otherwise be perfectly sufficient will then fail you at every turn.

      I suggest to get a new power supply every time you build a new computer (unless it’s like every year, then there’s surely at least one or two years still left in it).

      • Victuz says:

        It’s a five or six year old Feel II power supply. It’s been crap from the beginning and it only got more crap as time progressed. I know I need to buy a new one but my priorities are a tad different nowadays.
        Priorities like, having food and running electricity

  23. Sakkura says:

    There is some lacking/erroneous information in this article. For example, practically all non-K desktop Core i5 CPUs can be overclocked 4 bins, ie. 400 MHz/0.4 GHz via the multiplier alone. Add on top some BCLK overclocking, and you can often get half the overclocking that a K-series chip is capable of.

    Add to that the fact that overclocking shows diminishing returns, and overclocking non-K CPUs is suddenly a lot more interesting.

  24. ripwind says:

    Overclocking the K-series processors is so easy that it always surprises me nobody does it. Those “imperceptible differences” people talk about add up over time – and most of them are very perceptible.

    With a non-stock cooler (I like the Zalman 212) you can get an i5-2500k from 3.3 GHz into the 4.2-4.5GHz range with little to no effort. That’s such a huge bump. And, when you add video card overclocking into the mix, it has even more of an effect on your games. In fact, the extra speed may allow you to bump up that draw distance a bit, or maybe use some AA or other nice features comfortably.

  25. Premium User Badge

    Joshua says:

    Memory overclocking may not be worth it, but it is still good practice to look up the specifications of your memory. RAM is always designed to run at a certain voltage, and at certain clockspeeds and timings.

    If you have a memory chip that is designed to run at 4-4-4-12 timings, your motherboard will probably still be running at 5-5-5-15, or something. This is not a bad thing, as it does not damage anything, but you are not getting the best out of the hardware either. So ALWAYS look up the specs of your memory and manually set all those settings.

  26. slpk says:

    I have an i5 650 running at 4Ghz. MSI Afterburner (or whatever the hell it’s called) took care of the rest.
    The point is: every motherboard manufacturer has an OC utility that instantly manages all the crap for you.

  27. MiniMatt says:

    Jeremy, now you have your own little Hardware hobbit hole firmly nestled within the Hive can I make a request?

    Shut the buggery bollocks up!

    Not you; I was talking to my computer. Sometimes it talks back, but mostly it just thunders at me with a deafening roar of which even Horace would be proud. That is to say, one of my prime decision factors in buying hardware for a gaming PC is noise (which I guess roughly means we’re looking at performance per watt, with most of the noise coming from fans to cool the small nuclear reactor attached to modern graphics cards, but also a bit about fan design and size too).

    A quiet PC not only allows one to fully appreciate the death throes of my enemies in glorious surround sound, but allows the PC it’s rightful place as entertainment hub of the home rather than banished to some egg-box lined bunker at the bottom of the garden.

    • sinister agent says:

      But the gentle whirring of fans is the white noise that helps me sleep!

      (I have it auto-shut down after inactivity, leccy-saving fans. Fear not.)

  28. Bensam123 says:

    I would highly advise as another reader has pointed out to stress test your build!!! This can easily be done with a program like prime95. Even if your computer boots into windows and appears stable, that DOES NOT mean it is stable.

    Why is stability important? Because if you don’t make sure it’s stable you’ll find corrupt files popping up on your hard drive. Depending on how stable the computer acts while still throwing errors in the background it may not be something you’ll notice or ever even figure out.

    Usually bumping the voltage slightly can fix errors and remember a little voltage goes a long way.

    • Savagetech says:

      I’d like to add that monitoring your CPU temperatures is important when overclocking. I recommend running something like Core Temp to monitor your CPU temperature over time, especially during stress tests. Most CPU’s have a temperature shutdown limit (alluded to in the article) but their ideal operating temperature is far below that limit. If you don’t monitor your temperature, you can run your system too hot and not notice stability problems until you’ve damaged the CPU through continual overuse.

  29. optimusfunk says:

    You didn’t even talk about the most important part of overclocking… THE LED’S!!!! remember blue for extra cooling and red for extra power

  30. theleif says:

    Arstechnica just published a huge, pretty in depth but pedagogic, 18 processor test that I’d recommend you all to read. Take a look!

    What surprised me the most was that BF 3 was the least processor dependent game of them all. I would have thought it was the other way around.

    I would also recommend the linked article about a new way to compare graphic cards. Interesting read. Long story short: You should focus more on FPS latency instead of only average FPS.

    • Premium User Badge

      Joshua says:

      Battlefield 3 is pretty CPU heavy when it comes to the multiplayer – especially on 64 man servers. The SP experience is pretty CPU light however.

    • theleif says:

      Yeah, that makes sense.

  31. Initialised says:

    You should always OC your hardware as close to the limits of it’s cooling and your abilities as possible for gaming or HPC applications. Otherwise you’ll never learn how to fix your PC when things go wrong and you push it too far!

  32. Carra says:

    I have a nice i5-3570K and a Scythe Mugen. I haven’t bothered to overclock it beyond the motherboard overclocking option.

    Seeing how you can get it to get 1 ghz extra, I’ll have to look into it. Why else did I buy a K version with a cooler…

  33. LTK says:

    Jeremy, how do you think Intel’s Turbo Boost utility compares to manual overclocking by BIOS? According to this rising and falling bar graph it’s pushing the clockspeed up at least 400 MHz at some points. It seems almost deceptively simple to be a viable alternative.

  34. kibble-n-bullets says:

    I enjoyed reading that article even more than the author hated writing it.

  35. absolofdoom says:

    Seriously guys just do what it says in the article and then run away. Otherwise you might end up a crazy watercooling maniac like me.

  36. Uninteresting Curse File Implement says:

    Getting more performance for free is nice and all, but you must be crazy if you think I’ll be doing this:

    Then reboot and then repeat, but in 100MHz increments from there until falls over.

    Until it falls over? What the hell does this even mean? I’m not running experiments on my only PC waiting for it to crash or worse. It keeps crashing once a week as it is. It can’t be good the hard drive and system.

  37. Uninteresting Curse File Implement says:

    Also, is Dark Souls a CPU- or a GPU-bound game? Effing Blighttown, man.