OK, I just did a calculation off the POGs WUS for you (it varies with different projects!). The ratio of the Xeon L5420 @ 2.50GHz to the i7 3820 @4.5GHz is 1.69:1.
So the 8 threads the i7 is running at 4.5GHz are equal to 13.52 XEON L5420 cores. (when I O/C to 4.75GHz, the ratio goes up to 1.75:1 or 14 XEON L5420 cores to = 8 i7 threads, but that is truly O/Ced to the hilt.)
As JPM said, if you have more efficient XEONs (sounds like you do!) then it's more favorable to the XEONs.
I have 1 E5345 @2.33 with 8 gb Ram and 2 e5440 @2.83 with 16gb ram.
Having 5420s and 5650s, there is a HUGE difference.
@fouroh, I hide my computers, but if you look up Susa member Haunted Forest on Rosetta, eon, or Leiden, he has a system exactly like the one you're describing.
Most of my fleet is 56xx series. When you get those spinning up, they can pull down some credit. The threads make the difference. 2x5650s give you 24 threads.
Vic (mobile)
Wow, thanks for all the feedback! I'm down in New Orleans for the weekend, but when I get home I'll get on top of this project!
Update: I've purchased the Dell Precision T5500 (Dual Quad Xeon, 6Gb Ram, 2x250Gb HD, 875W Silver PSU, Win7 Pro) here-
http://www.ebay.com/itm/251445663395 Seller accepted best offer of $255
I also purchased two Xeon X5650 Hex-Core processors here-
http://www.ebay.com/itm/131092988378 Seller accepted best offer of $245
I'll probably end up needing more memory (1Gb per core?) but $500 all in for a complete 24-Thread machine isn't bad! Should be up and running by 2/18, helping in the POGS challenge and keeping my guest bedroom warm.
Wow that's a really great deal. Grats on your new build
Very nice! FourOh!!!