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robotech_er

GS performance on fermi?

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robotech_er    105
GS on G80 is very slow, and get much better on GT200(FX3800), how ever still can not get me fulfilled.
How is the situation on Fermi card, which i did not buy one yet, such as GTX570/580?
I want to output up to 64 vertices in GS, will this heavily jeopardize the performance on a fermi card?
any tools can test gs performance?


thanks you guys in anvance.

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MJP    19755
[quote name='robotech_er' timestamp='1312911631' post='4846784']
I want to output up to 64 vertices in GS, will this heavily jeopardize the performance on a fermi card?
any tools can test gs performance?
[/quote]

I have not run any tests myself, but that kind of GS amplification is a fundamental problem for GPU's and I'm not aware of anything new in Fermi that would change that.

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robotech_er    105
[quote name='MJP' timestamp='1312923750' post='4846889']
[quote name='robotech_er' timestamp='1312911631' post='4846784']
I want to output up to 64 vertices in GS, will this heavily jeopardize the performance on a fermi card?
any tools can test gs performance?
[/quote]

I have not run any tests myself, but that kind of GS amplification is a fundamental problem for GPU's and I'm not aware of anything new in Fermi that would change that.
[/quote]


thank you MJP. it is said that gs maybe get deprecated in future because of performance issue, is this possible?

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SergioJdelos    468
[quote name='robotech_er' timestamp='1313058391' post='4847594']
[quote name='MJP' timestamp='1312923750' post='4846889']
[quote name='robotech_er' timestamp='1312911631' post='4846784']
I want to output up to 64 vertices in GS, will this heavily jeopardize the performance on a fermi card?
any tools can test gs performance?
[/quote]

I have not run any tests myself, but that kind of GS amplification is a fundamental problem for GPU's and I'm not aware of anything new in Fermi that would change that.
[/quote]


thank you MJP. it is said that gs maybe get deprecated in future because of performance issue, is this possible?
[/quote]
Geometry Shader has it uses, but is not for tessellation. I read somewhere that GS output operate at full rate if you output 20 or less floats, 20 to 40 is half rate and so on...


In personal experiments I found that my 460gtx (336 cuda cores) is much more than 3 times faster than my 8800gt (112 cuda cores) in the only GS that I have, which is a GS for Cube ShadowMap Generation outputting position (float4) and, if required for alpha test, uv (float2). I do back face culling and frustum culling on the GS so usually it output less than 20 floats.







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