Which Processor is Best E 8400 or core 2 Quad?

i7 divides 4 cores over 4 paths, core 2 quad divide 4 cores over 2 paths, core 2 duo's divide 2 core over 2 paths. in short unless you are using socket 1366 (i7) then a dual core will outperform a core 2 quad most of the time!

core 2 duo means it has 2 nucleus of 3 ghz, the core 2 quad has 2 real nucleus and 2 virtual nucleus. This doesn't mean that you have either 6 ghz or 8 ghz. It means that if there are more processes run in the same time, if one nucleus is full than the second nucleus is activated to process the other operations. So it's up to you! If you want more processing power buy the core 2 duo, if you want to preform more tasks at the same time than buy the core 2 quad

I thought getting the e8400 would be better at one point due to there only being a few apps that take full advantage over quad cores, but my old Q6600 blows my e8400 away in almost all desktop tasks, aside from calculating pi single threaded.. Means they are about the same price, id definitely go with the quad. totally worth the little extra cash.

I would prefer Quad Core because I has 4 cores up and runing. Dual core can't give you more performance like Quad Core does becasuse Dual Core only have 2 cores. This also depends on cache memory. But 4MB L2 cache in Quad Core is good. Core means number of precessors. i.e., Core 2 Duo is 2 processors. Quad Core is having 4 processors. Now you deside which one is better. In short Quad Core is 2x faster then Dual Core. Don't look at cache this time.

Go for the Core 2 Quad. There's not much it won't run, and it being quad-core will certainly help with multi-threaded applications in future. If its a little too slow, a small overclock goes a long way.