A personal record of understanding, deciphering, speculating and predicting the development of modern microarchitecture designs.

Wednesday, May 19, 2010

GPGPU and its battle of nVidia vs ATI

GPGPU seems to be really taking off. I came across a new YouTube video showing IBM new mainstream server using nVidia Tesla graphics cards for compute intensive acceleration.

For the past few years, AMD/ATI enthusiasts have assumed that Radeon is AMD's crown jewels. The truth might be just the opposite.

At a workshop in a recent conference, an nvidia researcher compared CUDA and OpenCL. His argument (whether true or not) was simple: OpenCL is more a device driver level language. He "proved" it by showing the same program written in CUDA and in OpenCL side-by-side. The CUDA one took about 2 slides. The OpenCL about 10. If you are a researcher/programmer/engineer, which one will you use?

It may be true that ATI Evergreen gives higher performance per dollar for games, but nVidia Fermi seems to give better GPGPU performance on average. Evergreen has more parallelism and higher theoretical flops, but Fermi is easier to program and to get real speedup. Hundreds universities worldwide are teaching students how to optimize their programs for Fermi. This is a formidable rival and I don't share at all the optimism of many ATI enthusiasts.

I believe In a year or two we will see the market of GPGPU surpassing that of enthusiast graphics. Very few people in the world care about fps when playing games. On the other hand, everyone benefits from GPGPU. I feel that AMD/ATI is too conservative in pushing for GPGPU. Most of their laptop/desktop chipsets still use r700 or even r600 based IGP, which are very hard to get good GPGPU performance, if any at all. Every time I see a laptop with HD42xx IGP I feel disgusted. They are selling those 2-year-old stuff which doesn't let users take proper advantage of OpenCL. They sell them for cheap, but is it a good thing? Do they also want to sell r800 IGPs for cheap 2 years from now?

Then it's OpenCL which everyone's heard of but few is interested. In my humble opinion, AMD should hire a few programmers to fully integrate OpenCL into their Catalyst driver, so that every computer with an ATI GPU can use them after a simple driver install. In contrast, perhaps for fear of Microsoft or whatever reason, AMD/ATI want end users to manually install and upgrade every OpenCL release to match the installed Catalyst driver. If I'd go so much trouble then why don't I just install CUDA which more people are using anyway?

And if I'm going with CUDA, then I will not only buy Tesla for my workstation, but also GeForce for my desktop & laptop; there will be less incentive for me to buy an AMD CPU as well. That is really a good way to keep me away from being AMD's customer, isn't it?


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Peter said...

I believe that if AMD aren't inegrating openCL/stream into their drivers now then they will be in the near term.

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