Here's the upgrade I settled on:
- NVidia 9800 GTX video card
- 3 Gigs of triple channel (1333 MHz) DDR3 RAM
- Intel Core i7 (2.67 GHz) chip
- ASUS P6T Deluxe motherboard
I can't describe how much snappier everything is.... must be, on average, about 3x faster. It still annoys me that I had to do this. My new hardware is only about 23% faster (clock speed), so clearly there was some weird driver/hardware issue. With my new, well-supported Intel hardware, however, the driver support seems perfect. My 4 hyperthreaded cores are detected as 8 total processors, and the OS appears to load balance intelligently.
I highly recommend this setup. You will NOT be disappointed!