Wrong. I'm using 306.23 or whatever, the absolute newest NV drivers to power my 9800GT, which is doing Physx for my 7970's. Isn't that just a NV issue? I don't know if it's got better. But I remember hearing about people who bought the same GPU from different PCB makers and they wouldn't work together. But running 470's in SLI with 2 more diff gen cards in SLI, maybe thats the problem? Either way, won't matter much if your just using it for Physx, why not sell it and pick up a better single GPU for the job, granted I guess it don't matter much since a 275 should be more than enough, will save on some power usage though.