strange cycle numbers on nvidia cards

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6 comments, last by softimage 19 years, 10 months ago
Using a tool called nvshaderperf, I checked how many cycles my shader program costs on different cards. The assembly code compiled by dxsdk is 32 instruction slots long. For 5200 and 5600, the cycle number is 45. For 5700 it''s 28! For 5800, it''s 45 again! For 5950, it''s 28. Why isn''t it becoming fewer and fewer? And how can there be such a big gap between 5600 and 5700, while it''s not as big as this concerning about the difference in speed.
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I''m not 100% sure of the capabilities of some of those older cards, but I''ll wager there are fewer texture units on the 5200/5600/5800 vs. the 5700 & 5950.

Wasn''t the 5700 the top-tier card before the 5900 came out?

That''s a lot of video cards.

---------------------------Hello, and Welcome to some arbitrary temporal location in the space-time continuum.

the 5700 and 5950 are the newer card so i suspect they have slightly different shader units
I have seen on their web site they have something called the "CineFX engine" and there are 2 versions of it. This might be linked to your observation. Perhaps asking nvidia directly would be the fastest and most reliable way of knowing the definitive answer.
Wasn''t the nv 5800 that ''dustbuster'' card that completely bombed out on the market? I think they even discontinued it shortly after it came out. Maybe I''m thinking of one of the other FX cards, though.
Dustin Franklin ( circlesoft :: KBase :: Mystic GD :: ApolloNL )
Etnu is on the right path here. The 5200/5600/5800 are all based on the NV30 core. The 5700/5900/5950 are all based on the NV35 core. It''s not too surprising that a 5700 can outperform a 5800 in certain tasks.

neneboricua
Ok, I downloaded the program and it just says it''s unable to compile my shaders (which compile just fine in my game...). Is there something special about this program I''m missing? It seems like it''d be pretty damn useful, if only it did what I want it to do.

---------------------------Hello, and Welcome to some arbitrary temporal location in the space-time continuum.

It''s a matter of execution resources and the optimizations the drivers make.

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