N

not sure, I have two I-7's, one 3.01 ghz, the other 3.4 ghz.  Both have 12 gigs memory, the older, 1tb HD, the other 2tb.  Both Win7, for what that's worth.  The small difference between the speeds isn't noticeable, too little to  make much difference.  Memory, probably not the worst to go extra for.  Graphics card, not sure how much difference that makes, both of these came with pretty high end cards, okay, high end of the middle bracket.  No problems with either, and I've loaded it down with multiple figures more than once.  The only thing I've found that will bog it is using a tree generated with PovTree, two of them make Poser very slow, three will usually put an end to the foolishness. (Meaning locked up so tight the only thing that will work is the reset button.)  Processor speed, I can't compare Intel vs AMD, I have AMD in other computers,  but nowhere near the speed of the two I actually use. 

Probably processor speed first, and as much memory as you can afford.

D.

The "I" in Doric is Silent.