I can tell you that, unless you are running a 64bit Operating system, that anything above 4gigs doesn't matter. 32bit OS only use up to 4gigs of ram, and actually show having less than that, due to some addressing limitation i think.

So in short, No difference between 6gigs-8gigs of ram on 32 bit OS.


As for the cpu question, I don't know. Performance isn't just a measure of cores, or mhz. However, I think 500mhz, considering if it's a quad core is quite a big jump in performance.