Here's the first pass:
http://www.widescreengamingforum.com/wiki/index.php/WS_and_WTH_Benchmarking_%28Core_i7_920_and_9800_GX2%29
Gonna add a few more, then drop in the GTX 295 I have sitting here.
Are you running a single GTX 295 ?
If you have another graphic card (8xxx series or higher) sitting around, would you please take a little time to install it as a secondary card dedicated to processing Physx?
My primary concern is whether this will work or not as I read in another forum where a few people report that they cannot get the GTX295 to work with another Physx dedicated card as the system recognizes the GTX295 as in SLI and wont allow it unless the SLI is disabled (ie only 1 core of the GTX295 performs. But obviously this is not a desired solution). Those people also report that this happen for 9800GX2 as well.
BTW, I have checked Nvidia website about Physx configurations. One configuration ("Multi-card") is Card A (for graphic rendering) works together with Card B (for Physx) and Card A does not have to be the same as Card B. However, it does not specify if Card A can be a dual-core graphic card (internally SLied as the 9800GX2 or GTX295).
PS What is your OS?