My main box is an old but trusty Lynnfield i5 750 in a P55 LE 'board with 8 gigs of DDR3-1600 and a 1 gig Geforce GTX 550 Ti, dual-booting between Xubuntu 12.10 x64 and Win7 x64. I've decommissioned and sold a spare Core 2 Duo CPU/RAM/mobo combo recently, but am now left with a spare 512 MB 9600GT. Since the motherboard has a spare PCIe x16 slot, I've thought about throwing it in there and basically using it as a headless coprocessor, mostly for PhysX in Batman: Arkham Asylum, Unreal Tournament 3, and Cryostasis, and BOINC or a few scientific computing applications in Linux. Are there other instances where it could be useful? The system's running a nearly new Corsair 600W PSU, so that shouldn't be a big problem. Thoughts and suggestions are appreciated.