I know there is a similar review done by miahallen i think it was? But I decided to investigate how much the processing power of a dedicated PhysX card can affect game framerate - eg Mafia II
It is often said that the number of shader units are key to the PhysX processing capability of the dedicated card. I wanted to check this and also how core and memory speed will affect framerates.
System:
E8500@4.1ghz
GTX470 (OC - 760Mhz)
9800GTX (ded. PhysX)
2GB DDR3 1500Mhz
MAFIA II Demo
PhysX HIGH
1280x1024
16xAF+AA set in game
Testing method:
I used MSI Afterburner to DOWNCLOCK the 9800GTX to the minimum possible speed (505mhz Core, 1263mhz Shader clock, 825mhz Memory) . Then I increased Core, Shader and Memory clocks in turn to see how they affected framerates.
Finally I overclocked the card by 15% to see if I could squeeze some more fps out of it.
Results:
"Tryed putting images in so i have to direct link you guys"
http://img508.imageshack.us/img508/3932/avggraph.jpg
http://img522.imageshack.us/img522/6941/tablel.jpg
No real surprises. Shader capability is indeed where it's at for PhysX processing. Out of the 3 variables, increasing the Shader clock gives by far the greatest gains. It should be noted that Afterburner would not allow me to leave the Shader clocks at minimum when raising the Core, so the raise in Core clock is less effective than the chart implies.
It was interesting to see that a 15% overclock on the 9800GTX did give significant gains in fps.
Conclusion:
Bump up your Shaders! It is definitely worth overclocking your dedicated PhysX card if you are using a 9800GTX or slower card. I imagine that you will get diminishing returns with GTX275 and upwards but if you are lucky enough to be using such a card for dedicated PhysX, why not? You can leave or even downclock your dedicated GPUs core and RAM in an attempt to get the max shader clock possible.
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Originally Posted by Massman
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