uh one copatibility issue I can think of off the top of my head is that Poser 8 is a 32bit application.

the i7-920 is dual cpu yes?  Quad will be faster in most regards.

Now with Poser Pro (Poser 7 with 64bit rendering available) and a quad you would be smoking. 

to be completely compatible with windows 7 etc you'll have to wait til Poser Pro 2 (poser 8 with 64bit rendering available)

Since your talking Poser 8 - your gunna be limited to 2mb of application ram under windows 7 due to the 32 bit poser 8.