Right now I'm running dual Xeon 5160's (dual core 3ghz). I've been considering upgrading to dual Xeon E5345's, (quad core 2.33ghz). Would it be worth it to run more cores of a slower speed? The cost of the upgrade isn't a factor. And these are the two fastest CPUs I can run on my motherboard. The system is the HP xw6400 in my signature.