What are the benefits of a dual-core CPU over a quad-core in a desktop PC?

"Check out these posts from Coding Horror:

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I will never say no to more cores/processors. I can always find something for them to be doing. Besides, I can't notice a difference with my Intel Quad Core versus my Intel Dual Core when gaming; perhaps my video cards mask the difference.

"Unless you are a heavy gammer you'll never need that much power ever...
RAM are more useful to a typical (non gaming) desktop PC, seeing that even a webbrowser nowadays can take about 300 megs of ram from a lilttle more than just light browsing..
Typical word window takes up about 20mgs or so but people usually run multiple...
And vista itself is a big hog.. but typically a midline cpu can handle these... even on a quadcore.. usually the program will only strain only one of the cores..."

The Cache may have a major effect, 4 core CPUs tend to have smaller caches (there's only so much silicon) and having more processes running flushes out the cached data you need for a given process.

It depends alot on what you're doing most of the time I think. If what you do involves using several different programs, for example, web development with TextMate, Photoshop, Transmit, Versions, etc., then it might be advantageous to have a different processor able to handle each. If on the other hand, you're only running one program and need it to be able to run fast, like video editing perhaps, you'd probably less, faster cores. At least until more programs are able to make use of multiple cores.