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Earlier this week, AMD launched Kaveri, its first part with Steamroller cores. People mostly weren't impressed, and while the commentary here was muted, the part could have justified scathing if you only look at the top bin. People mostly focused on what happens if you clock the CPU around 4 GHz for a TDP in the neighborhood of 100 W. And there, Kaveri is simply mediocre.
Kaveri isn't good at clocking high for good single-threaded performance, which is what good desktop CPUs need to do. But it was never meant to be. We didn't realize what AMD was up to, but now I think I do.
As you probably know, AMD is a much smaller company than Intel. They don't have Intel's money and they don't have Intel's fabs. If Intel wants to be good at something, and AMD wants to be good at the same thing, Intel can throw vastly more money at it than AMD and Intel will win. For AMD to be somewhat worse than Intel at everything would mean that they're always and forever relegated to be a budget option in all categories. That's not a good way to make money.
But Intel can't be good at everything. They can't make 20 different CPU architectures to have something ideally optimized for every market imaginable. For many years, Intel essentially had one architecture. Atom made it two, and Quark kind of makes it three, if you think Quark matters, which I don't. But if AMD can build chips that are good at the things that Haswell and Atom aren't, then AMD could be the premium vendor in some markets, and make a lot of money that way.
And that's exactly what AMD has been trying to do. One area that AMD has focused on is graphics, especially integrated graphics. That's why AMD bought ATI: so that they could have vastly better integrated graphics than Intel in a future in which most people used graphics integrated into the same chip as the CPU.
Another area where Intel was deficient is that there was a gaping chasm between Atom and Intel's high end architecture. Bobcat and now Jaguar cores were designed to fill that gap and did so admirably. For about 2 1/2 years, about the only reason to buy an Atom chip was not knowing any better, though with Silvermont cores, Atom is finally competitive.
This year, AMD is trying to crush Intel with Steamroller cores about the same way that the Radeon HD 4870 crushed Nvidia in its day. Given comparably good architectures, more cores clocked lower beat fewer cores clocked higher if your workload scales well to more cores. Graphics scales well to as many shaders as you can throw at it, which is why the Radeon HD 4870 kicked off an era in which AMD handily beat Nvidia in the various efficiency metrics for three generations before Nvidia's Kepler was forced to adopt AMD's approach of more shaders clocked lower.
But CPU workloads don't scale well to many cores, you say? That's ot quite true; some CPU workloads don't scale well. AMD wasn't going to be able to beat Intel in those workloads anyway, so they decided to focus on where they could: CPU workloads that do scale to many cores.
Even so, AMD had been trying to do this for years. Barcelona (Phenom) was the first chip with four x86 cores in a single die. Magny-Cours had 12 Phenom II class cores in one socket. Interlagos had 16 Bulldozer cores. Abu Dhabi has 16 Piledriver cores. The last three of those were all dual-die multi-chip modules. Magny-Cours fared okay, but the others were crippled by having a bad underlying CPU architecture. If the CPU cores are bad, a good die configuration of bad cores can't save the chip. Abu Dhabi was roughly competitive with Intel's Xeon E5 chips in workloads optimally designed to favor AMD--and got completely killed in most others.
With Steamroller cores, AMD finally has the architecture to deliver the product that they wanted. AMD pushed Kaveri reviews in this direction, though we didn't notice it. Usually CPU reviews do the top bin to showcase top-end performance. AMD pushed for more emphasis on the lower power A8-7600--to the degree that some sites only looked at that bin and not the higher power A10-7850K. Furthermore, AMD pushed for sites to show what the chip could do both at 65 W and 45 W. At 95 W, it's not that much faster than 45 W--which is why at 95 W, it's an unimpressive chip, even though at 45 W, it's quite nice.
The problem with this is that in a desktop, the difference between 45 W and 95 W doesn't matter much. But what AMD can--and probably will--do is to make another chip that strips out the GPU and has about 16 or so Steamroller cores in the neighborhood of 3 GHz and a TDP around 125 W. That would be a compelling chip, and vastly faster than Abu Dhabi in the same TDP.
To be fair, Intel can make a CPU with a lot of cores, too. But have you seen what Intel charges for them? The cheapest Xeon on New Egg with more than four cores is $919, and that's for a low bin. There's plenty of room for AMD to undercut that and make a lot of money. AMD doesn't need to win 80% of the server market. If Steamroller cores can get AMD 20% of the server market, that's enough to declare victory.
But servers aren't the only market that would like to clock CPUs closer to 3 GHz than 4 GHz in order to save on power. There are also laptops. While laptop workloads don't scale well to many CPU cores any better than desktop workloads, you're not going to put 16 cores in a single laptop socket. Or 8, for that matter. There might not be that many desktop or laptop programs that can get much use out of 16 CPU cores, but 3 or 4 is a different matter. If AMD offers four cores for the price of Intel's two, and AMD's four cores can clock respectably, that could be a nifty product. With Kaveri, they will.
You could clock Piledriver cores around 3 GHz, too. But they still used a lot of power, without having the performance to justify it.
You may laugh at AMD's approach of more CPU cores clocked lower, as it's really not very useful in desktops. But consider that it's already paid off for AMD in some cases. Note, for example, the Xbox One and the PlayStation 4. This wasn't just a case of AMD winning purely because they had better graphics to pair with an inferior CPU. 8 Jaguar cores can offer more performance than two Haswell cores in the same low console-friendly TDP. Nor is it clear that in the same average CPU power usage as the PS4 and Xbone have, even four Haswell cores could have offered more performance.