Week in Tech: SSD Update - It's All About (NV)Me!

One word. NVMe. Take it from me, you want some of it. So, you'd better start to get your head around it. Luckily, it's all you need to know about solid-state drives or SSDs over the next year or so. Well, that and whether your motherboard can support NVMe. Oh, and the difference between M.2, SFF-8639 and SATA Express. I know. This whole SSD thing is a nightmare to keep up with right now. But let me simply say this: some early solid-state drives with that NVMe stuff I just mentioned have appeared in recent months, and these things absolutely fly.

Time, then, for an SSD update and for me to make something intelligible out of the technosoup that is emerging SSD tech. Also, can there really be any of you left without an SSD of some kind? If so, shout out below and let's see if we can all encourage the laggards to finally make the leap. SSDs are cheaper than ever (an eminently viable 100GB-120GB drive can be had for as little as about £50 / $70, possibly even less with some deft shopping), and I can promise that you will not be disappointed.

Quick note to start with – if you just want to be told what SSD to buy, do not pass go, do not collect a boxed copy of Windows ME, just go straight to the TL;DR bit at the bottom. Everyone else, get comfy.

Right, then, solid-state drives. What a 'mare. They're impossible to benchmark properly. Every time you think you've got your head around them, the technology changes or some new metric of performance tears up everything you thought you knew. As for how long they actually last before going titsup.com, don't ask me. And yet. And yet. SSDs are bloody brilliant at making your PC feel fast.

The thing about SSDs is that they're different. Different from the likes of processors or graphics cards, I mean. Chuck the latter two through a benchmark over and over and you'll usually get the same result.

There are exceptions. Thermal throttling (too much heat, in other words) can cause clockspeeds to be capped and performance to be reduced as temperatures build, just as a for instance. And you can have problems with the thermal paste, pads and dust. But broadly, CPUs and graphics chips themselves don't really degrade over time. Not so for SSDs.

Intel's NVMe'ed, pure-PCI Express P3700 - is this what SSDs are going to look like?

It's pretty easy to know which CPUs and graphics cards are faster, too. Fire up your favourite game, measure the frame rate. Things can get a bit more nuanced when it comes to various image quality settings and things like minimum frame rates versus averages, AMD Mantle versus Nvidia GameWorks, whatever. But, again, it's generally not too hard to fathom how much cop a video card is. Not so for SSDs.

If the early days of SSDs were a stuttering mess, even now drives from big brands can throw up problems. Even the mighty Samsung colossus, which bestrides the SSD landscape like a very large bestriding thing, recently released a firmware update to resolve performance degradation over time with its 840 Evo drive.

That's a drive I have myself suggested as a great all rounder and value proposition. Shocking. However, that SSDs are still completely worth it despite the Rumsfeldian flaws (the known unknowns of performance degradation are joined by unknown unknowns that, well, we don't know about until they emerge) tells you a lot about just how big an impact they can make on your PC.

That includes gaming. OK, a lot of games load up a level and don't require much mass storage access until the next. But getting in and out of your favourite games will be so much speedier. I don't know about you, but I get properly agitated waiting for games to load. Must be the attention deficit.

Whatever, frame rates will settle down much quicker after a level load, too, and for those games that load data on the fly, an SSD will help smooth things out very nicely. If that's the sales pitch, what's the big news with SSDs right now? It's that NVMe thing and the related emergence of super-fast PCI Express-based drives. We've been talking about them for some time. But we still haven't quite got there.

It's all very confusing and a bit frustrating. For starters, what used to be just good old SATA is being replaced by a rats' nest of new standards. There's SATA Express which vaguely fuses PCI Express with the old SATA interface. M.2 is a new interface that does away with the physical aspects of SATA but not immediately its signalling properties.

There are pure PCI Express storage cards, too, that plug into slots much like a graphics or sound card. And don't forget SFF-8639 which is a cross between SATA Express and SAS, is intended for enterprise systems but looks so good I want it in my PC. Confused? I bloody well am.

Until NVMe drives for punters appear, you can do a lot worse than a cheap Crucial drive

So far SATA Express has conspicuously failed to catch on – I've seen motherboards with SATA Express ports, but not a single compatible drive – so I'm rapidly approaching the conclusion that it could well be a stillborn interface. Phew, one less interface to worry about.

Of the rest, M.2 looks like the most likely candidate for widespread adoption. Both compatible motherboards and drives are already on the market. M.2 calls for tiny little cards that are physically similar to the mSATA SSDs commonly seen in laptop PCs. We're talking mini PCBs with exposed chips available in multiple lengths and capacities.

Intel's latest 9 Series motherboard chipsets (so Z97, H97 and the rest) support M.2, though that doesn't guarantee a given 9 Series motherboard will have an M.2 slot. The problem is that all the M.2 drives I've had my hands on so far have not delivered on the second part of the next-gen SSD revolution. At last, we come to NVMe.

So far, early M.2 drives have used the old AHCI storage control protocol. Think of it as the control language for hard rives. And AHCI was designed for just that – hard drives, not solid state drives. NVMe or Non-Volatile Memory Express (now you wish you hadn't asked, right?) is a new protocol designed specifically for SSDs.

We've touched on this before and discussed how NVMe promises to slash latencies but really the technicalities aren't important. What's important is that the limits of SATA haven't just been about raw bandwidth. The AHCI protocol has been holding things back, too.

That remains largely true right now. As far as I know, the very first NVMe-capable SSD was Intel's SSD DC P3700, a pure PCI Express plug-in card for servers. The smallest variant starts at 400GB and it's priced at about $3 per GB, so it's not exactly an option for most gamers.

If you want a taste of what these new NVMe PCI Express-based drives can do, get a load of these numbers offered by a new Samsung drive (it's a SFF-8639 aimed at enterprise customers, not punters and gamers, sorry). The XS1715 in 1.6TB trim will do 3GB/s reads and 1.4GB/s writes. Nice. SATA drives typically top out at about 550MB/s each way.

But the most eye-popping number is the 750,000 read IOPS (the write IOPS aren't quite as impressive). Samsung's top SATA drive for the likes of you and we tops out at 100,000 IOPS. The random access performance of the XS1715 must be smoking.

As I've also mentioned before, SSD controller chips with NVMe support have been announced, but actual consumer drives are nowhere to be seen, as far as I know.

And still we wait for mainstream SSDs with NVMe-capable controller chips...

Put that altogether and what we have is a post that might as well have said, “still waiting for SSDs to get faster, nothing to see here, move along.” But seriously, at least now you know what's coming (NVMe) and what you'll likely need to get hold of it (an Intel 9 Series motherboard and an M.2 drive).

Until that happens, watch this space and my advice hasn't changed. Buy a cheap and cheerful Crucial M500 to tide you over.

TL;DR:
- Something called NVMe is coming and it's going to make SSDs stupid fast
- It's not quite here yet
- You'll need an Intel 9 Series motherboard, too
- So for now, buy something cheap but effective (I'm sticking with my Crucial M500 advice) that works with your existing motherboard if you don't already have an SSD