Published in Graphics

Radeon HD 2000 supports Vec5 superscalar


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320 SPs up to 40 percent faster than G80 (in theory)


Until today we believed that the R600 is a Vec4+1 scalar chip, which sounded very inefficient to us. We had a chance to take a peak at some DAAMIT documents and learned that ATI wants to present the R600 as a superscalar chip with 5 instructions per clock.


Previous ATI hardware, including the Radeon 9600, 9700, 9800 and X series could handle two instructions per clock with 3+1 or 4+1 components.

The Radeon HD 2000 series supports Superscalar marchitecture and it means that with Vec5 or Superscalar, ATI can process 5 scalar instructions per clock. It has 64 Unified Shaders and by multiplying these two numbers you end up with the amazing number of 320 Stream processors.

The Nvidia G80 GTX can only handle Vec4 instruction in a scalable way, or four independent instructions, and it looks like ATI might have an advantage here. Nvidia can process 128 Stream processor instructions, but at the much higher clock speed of 1.35 GHz, while the R600 can do 320 Stream instructions per clock, but at close to half the speed or 750 MHz.

In raw numbers, the G80 at GTX clocks can handle 172.800 Millions of instructions or Shaders if you like, while the R600 can handle 240.000 Million Shaders per clock. If this turns to be right, ATI could run Shader instructions - especially the unified ones - up to forty per cent faster.

Well, this will only be noticeable in next generation games and benchmarks, so you still have some time to wait for this revolution.   

Last modified on 30 April 2007
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