Originally posted by: Keysplayr
Originally posted by: cmdrdredd
I just installed a 9600gt as a physx card. here's my problem or my question. How come I went from 45fps average in cryostasis with just a GTX295 to 77fps average, yet I lose 4k points on 3Dmark and when looking at the results side by side I noticed the physx portion of the test was almost 1/2 what it was before. Am I to assume that 3D Mark is simply forcing multiple calculations on the card and not doing any real 3D work to simply get a max number of calculations per second, thus the GTX295 being set as the physx card would be superior in this test while a game that is rendering textures, lighting and geometry etc would benefit from offloading the Physx work?
I was speculating about this with Apoppin the other day. It is possible, that PhysX steals memory, memory bandwidth, and memory controller cycles when run on the primary card.
Offloading PhysX to another card that has it's own resources to draw from seems to be the best method for the most performance in PhysX games. While a single higher end card can handle PhysX pretty well, the reason for the rather large jump in performance "could" be as stated above. That could be why a 16sp 8400GS offered so much performance gain. At the same time, we are freeing up valuable resources on the primary card, and granted even more in the form of a dedicated PhysX card. So, it doesn't appear that PhysX is all that shader hungry, but it does "appear" to be bandwidth (memory) hungry. Thus the 256MB minimum requirement for any given PhysX capable card.
This is just a theory, I really have no info yet. I was going to configure some sort of testing on this. Just have to figure out how, and what to do.