ESXi and Xen white box

[jay-R5TnC2l8y5lBDgjK7y7TUQ at public.gmane.org (jay-R5TnC2l8y5lBDgjK7y7TUQ at public.gmane.org)]

I'm putting together an esxi and xen white box to play with and do some testing.  And was drawn in by the value of the new athlon II x4 620. $99 for a 2.6 quad-core is hard to beat.  The rest of the system would be running a gigabit 770 board with 8gb of ddr3 1333. But I'm considering two other options and figured I would get some input.

First option is the phenom II x4 925 - $150: upgrade to 2.8ghz and a 6meg L3 cache (same 4x128-L1 & 4x512-L2 as the athlon). Not sure if there is really much else different that would effect my use. 

Will the 6megs of L3 make a signifigant difference? And does phenom II ofer any other benefits over athlon II?

Second option is a scavanged core2duo e8500: currently running my main desktop so I'm leaning away from this option.  But if the beast of a dual core could compete with a quad, in a virtualization server I may consider the option.  But also I would be sticking with ddr2 800, rather than dd3 1333, which it self would be a decent preformance hit.  

Could a fast dual core and ddr2 compete with a moderate quad and ddr3, at running a dozen vms?

Keep in mind this is not a production system so value over preformance is the goal.  And the cheapes intel quad option, with virt, is the Q8400 at $170. This also being financed through my newegg acount, so there are some availability limits. But if you have any suggestions, please let me know.

Thanks
Jason M Normand
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