Larrabee Dead. Not Surprised.

I had a lunch discussion last Thursday, and I predicted that Larrabee wouldn’t be a big success during a discussion. Then, on Friday I saw this article. Apparently, I’m more prescient than I thought. There’s a little more input over here on the Real Time Rendering Blog. The first Larrabee card isn’t going to be released, and I don’t think we’ll see great success from any successors. Pun intended. 🙂

When I look at Larrabee, I see a couple of hurdles:

  • It sinks or swims as a GPU.
  • Utilizing all the power requires very wide SIMD.

Larrabee’s biggest problem is figuring out how to get people to buy it. Developers don’t want to spend a lot of effort writing software for it if there’s not a large install base. Conversely, without some sort of software to give enthusiasts a reason to buy it, the install base won’t build. Looking at what’s out there, you have one major pillar for building an install base without a bunch of Larrabee native titles, DirectX gaming performance. Larrabee has to succeed as a DX GPU. Without that, it can’t make it as Larrabee. When you couple that fact with the reality that silicon from AMD and NVIDIA is targetted at being a great GPU first, it’s hard to believe that the very flexible Larrabee cards will be able to compete on a per dollar or per watt basis.

The second argument is that Larrabee will be big because x86 code can run on it with minimal modifications and be massively parallel. This is true. It’s possibly easier than getting code running through CUDA. I don’t know; I haven’t written any code for Larrabee. However, Larrabee uses 16 float wide instructions. I’ll bet money when there’s a report of floating point performance of X teraflops that it requires using those 16 wide instructions. If you port scalar float or SSE vector4 code to Larrabee, you’re still leaving 15/16 or 3/4 of the flops on the table. It will require hand tailored code for Larrabee., and then we go back to my first argument.

dba

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One Response to “Larrabee Dead. Not Surprised.”

  1. […] Not Dead in the Strictest Sense In a previous post, I said that Larrabee was dead. That post had some details about why I thought Larrabee […]

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