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Can AMD Make Gaming CPUs A Two-Horse Race Again?

That's Zen, not Xen...

The roulette wheel of rumours that is PC hardware news is usually pretty pointless, unless bun fights over shader specs or clock speeds are your bag. But, occasionally, something really significant for the future moves into view. This is one of those times. AMD has been talking about its upcoming PC products and technologies in the last week or two, including a completely new CPU core and some fancy memory technology that might dramatically change the way we all think about integrated graphics and gaming. Is Intel's stranglehold about to be loosened?

So, the new CPU core. It's called Zen and it's due next year. It's a simple fact that AMD's track record regards launching new CPUs on time has been poor for the last few generations, so I wouldn't make too many assumptions. But next year would certainly be nice.

Anyway, the thing about Zen is that it's a traditional x86 core for PCs. I mean traditional in the sense that it's being pitched as a proper high-performance architecture, not some ultra-mobile or embedded effort destined for the internet of things or whatever the prevailing fad may be. And it's claimed to be completely new.

In other words, the Bulldozer experiment is dead. Bulldozer is the PU tech that underpins all of AMD's current full-power cores. So that's the crusty old FX chips and the newer and shinier APUs with graphics on-die.

Zen is coming next year. Please, please let it be good.

Anyway, Bulldozer was meant to be a multi-threading beast thanks to a modular architecture that saw a pair of integer units sharing a floating point unit. Think of it as a bit like Intel Hyper-Threading, but with more hardware thrown at it.

It was certainly novel and made the question of what actually qualifies as a CPU core trickier than ever before. But as an actual CPU, things didn't work out so well. For starters, games still haven't become as efficiently multi-threaded as expected (though DirectX 12 might change that).

That's a problem because Bulldozer-derived chips suffer from fairly piss-poor single-threaded performance. It's not that they're terrible chips. I've been playing around with an FX-8350 lately and it's really not all that bad.

But for gamers, Intel's huge single-thread advantage (in the region of 100 per cent sometimes) is just overwhelming. AMD says Zen will boost per-core IPC or instructions per clock by 40 per cent, which is pretty epic.

If I'm really honest, even 40 per cent won't be enough to blow Intel away. But depending on clockspeeds, it should put AMD back in the game, so to speak. AMD is also promising to improve and revise Zen more rapidly and extensively than it ever managed with the Bulldozer family which has largely stagnated despite the Piledriver and Steamroller iterations.

Zen will also get a new socket, AM4, and I assume some new chipsets. The latter are long overdue for the FX line of desktops CPUs and hopefully will bring plenty of USB 3.0 and PCI Express storage goodness.

AMD says Zen fixes Bulldozer's rubbish single-threaded performance

Whatever, all the noises AMD is making about Zen are exactly what you'd want to hear as a PC gamer. It's a proper x86 design and it aims to improve performance and fix platform shortcomings in precisely the areas that matters for games. Bring on 2016.

The other interesting AMD development is a new tech known as HBM, which stands for high bandwidth memory. The shizzle here involves sticking graphics memory into the same package as the GPU or graphics chip itself. The idea is that putting memory near the main chip makes signalling much simpler and allows the bus width to be made much bigger.

The other cleverness with HBM is die stacking, or piling the memory chips atop of one another. You, or rather AMD, then connects 'em courtesy of TSVs or through-silicon vias. If that sounds a bit familiar, it's similar to the tech in the latest 3D-flash-memory SSDs, like the Samsung 850 Evo.

Will AMD's stacked memory tech finally make integrated graphic a goer for games?

Put the on-package memory together with the die stacking and you get a 1,024-bit bus and 100's of GB of bandwidth. Currently, AMD is pitching HBM as its next memory solution for graphics cards.

However – and this is where the rumours kick in – it's thought Zen CPUs will come with integrated graphics and that on-package HBM memory. If so, that could dramatically change the way we all think about integrated graphics.

Currently, memory bandwidth is a big killer for integrated graphics. CPUs make do with much lower bandwidth than graphics cards, which is a major problem when that limited bandwidth is being shared by graphics, CPU and every other subsystem. In short, it makes proper gaming graphics performance impossible.

However, with HBM, you have the potential for a single-chip PC that looks rather like an Xbox One or Sony PS4. Except it will probably be better and faster by every metric. To be clear, I don't think this will kill off add-in graphics card overnight. But it could present entry level and eventually middling gaming PCs with a more affordable option.

There are downsides, of course. With CPU, GPU and even memory on one package, your upgrade options are very limited. But then a lot of people don't do piecemeal upgrades. If that's you, Zen-plus-HBM could make a decent gaming PC more affordable than ever. Here's hoping.

Finally, what I haven't mentioned so far and what will actually arrive first is a new high-end graphics card from AMD with that HBM memory tech. It's due out this 'quarter' which means it should appear by the end of June. of course, it'll cost the earth and hardly any of us will buy it. So it goes.

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