The question is, is the more expensive build worth the price increase over the cheaper build (if it is only like, 30-50% faster i wont buy it over the cheaper one)? The pc will be used for Skyrim @ 1440x900 res. and a few older RPGs.
The builds cannot be changed in any way.
Basically, as far as I can determine, the more expensive PC is about 100% better, with twice the processing cores (most games do not take advantage of that though), twice the ram, twice the HDD and twice the graphics. My take on those, the second one is worth $150 more.