Choice of processors and motherboards

Hi

I have the choice between two computers and I hope you can help me out. It is basically a question of a faster processor and older motherboard versus a slower processor and a newer motherboard.

Comp 1:
Motherboard: Intel WARRENSBURG DP55WG
Processor: Intel Core i7-870 2.93 8M 1333
PSU: Antec TruePower Trio 650W
Hard drive: WD WD5000AADS 500GB/7200/32MB SATA II

Comp 2:
Motherboard: GIGABYTE GA-EX58-UD5
Processor: Intel CoreI7 975 3.33Ghz/8MB/6.8 GT/sec
PSU: ANTEC TP 750 80+
Hard drive: WD WD5000AADS 500GB/7200/32MB SATA II

I know that what's important is the combination of the different parts and that's where I lack the knowledge. I need to run heavy simulations which take days and so I would like the strongest of those two.

Thanks for any comments.
Hadassa