On my home PC, I recently installed a ATI Radeon 5870 which has been phenominal. It replaced a GeForce 8800GT SLi setup. I desired to keep one of the 8800s as a dedicated physics card. This actually worked flawlessly--until nVidia caught on, that is. These days all their driver releases look for ATI hardware, and if present, disable hardware PhysX on the GeForce card. In response to another angry customer, nVidia customer support stated they disabled the functionality for "business reasons" and not because of any sort of technical incompatibility. Their suggested solution, unsurprisingly, is to discontinue use of ATI products and use nVidia instead.
In other words, they are intentionally crippling hardware I paid good money for simply because I choose to have a competitors's part in the system.
I'm never buying nVidia again. This includes future upgrades for our CAD workstations. So do any of you out there use workstation-class ATI hardware for Solidworks? Has it been a good experience? Any problems? Recommendations? I design mobile machinery and sometimes work with 2000+ part assemblies.