It really depends on what you do on your system, don't waste money on a six core if it's only going to be used mainly for word processing and even just gaming. The Q9650 is still a great CPU and you shouldn't have much of a hard time with anything on that chip. Get the six core if you're really going to use it, Photoshop, CAD work, heavy gaming etc. Now if you can get the six core for cheap like you said, then it might be worth it in that regard. But you have to decide whether or not you're wasting money on something you really might not take advantage of anyways.
I'd probably go for around $210 on eBay for the Q9650. It's still an awesome chip.
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