ATI Radeon HD 4000 Series discussion

[AliG]

Exactly why the tmu count was raised and not the rop. Considering that its a superscalar design, the 32 TMUs would have been perfect for the r600 as that would have meant the same 2:1 ratio nvidia used with g80 (which seems to work perfectly). But seeing how the actual stream count has been raised from 64 to 96, I'd say I would have wanted 46 TMUs instead as g80 proved the 2:1 works while anything less offers performance issues.

Regardless, the rv770 will be here months before gt200 and it should bring in a lot of money. Besides, looking at how silent ati and amd were about the original r600 (before the gazillion changes) and k10, and how nvidia is always bragging and leaking out their highend stuff, I'd say they are facing problems with gt200

[LordEC911]

Exactly why the tmu count was raised and not the rop. Considering that its a superscalar design, the 32 TMUs would have been perfect for the r600 as that would have meant the same 2:1 ratio nvidia used with g80 (which seems to work perfectly). But seeing how the actual stream count has been raised from 64 to 96, I'd say I would have wanted 46 TMUs instead as g80 proved the 2:1 works while anything less offers performance issues.

R600 was 4:1 in terms of ALU:Tex
If RV770 really has 96 shaders then it would be 3:1

I think ATi should keep the Shader/TMU ratio at at least 3:1 as ATi also does the AA in the shaders. Oh and doesn't 480 stream processors equate to 96 shaders? I'm wondering what the amount of SIMDs will be on the RV770 though, but I'm not sure how important that is in terms of efficiency.

With 96 shaders it should be kept at 4SIMDs.
The rumored 160shaders was also rumored to be a 5SIMD approach.
The amount of SIMDs are important to efficiency due to the batch size.

[NH|Delph1]

R600 was 4:1 in terms of ALU:Tex
If RV770 really has 96 shaders then it would be 3:1


With 96 shaders it should be kept at 4SIMDs.
The rumored 160shaders was also rumored to be a 5SIMD approach.
The amount of SIMDs are important to efficiency due to the batch size.

Based on discussions with people in Taiwan, RV770 seems to employ 5:1 ratio and 160 shaders. Not that this is a fact, but it does look a lot more believable than anything else I've heard.

//Andreas

[AliG]

R600 was 4:1 in terms of ALU:Tex
If RV770 really has 96 shaders then it would be 3:1


With 96 shaders it should be kept at 4SIMDs.
The rumored 160shaders was also rumored to be a 5SIMD approach.
The amount of SIMDs are important to efficiency due to the batch size.

that's true, but I'm saying actual shader bundles, not stream shaders by ati's count