Actually it was at one point one of the best quad core CPU released some consider it a milestone. Q6600 as long as you give it a proper after-market cooler and can hit around 3.4Ghz should be fine for another 2-3 years or more depending on use.
For gaming it's a bit past it's prime at least compared to the latest. But if you mostly play older games or don't game much it's a very strong CPU. Many are still surprised to this day just how good it can be because many who bought the Core 2 brand went with the E8s and other dual-core. While those who went with the Q6600 were lambasted for buying a CPU, which won't be utilized much but to this day there's still a lot of Q6600s still being used because of just how good it was.
I definitely remember some of that Q6600 lambasting three years ago. But here's the situation I had at the time when buying CPUs:
Q6600. E6850. Same price (around $280). Same architecture (65nm Core 2). Same multiplier (9x). But one of them had twice as many cores. Can you say "no-brainer"?
Some still went with the E6850 anyway, thinking that the higher overclocking headroom due to dealing with half the heat and such would work out better in the long run. Then the 45nm Wolfdales like the E8400 showed up a few months later. I still banked on my Q6600 performing well enough with the clock speeds it could attain, with future games later utilizing the extra cores to greater effect, and I'd say it paid off.
Mine's only running at 3.2 GHz, but at a 400 MHz FSB. It's somewhere in the 3.4 to 3.6 GHz range that it needs a massive increase in voltage-too much for my Sunbeamtech Core-Contact Freezer to dissipate the resulting heat increase. Still, I can safely say that for anything that isn't Cortex Command or an emulator, it's the 8800 GT that's bottlenecking this system more than anything else.
I still might be tempted to step up to something newer if the price is low enough, but the main factor there is that I just had to end up dropping $145 on a P35 board, and then P45 shows up a few months later without the exorbitant X38/X48 price tag. I'm concerned about the PCIe 1.1 x16 slot not providing enough bandwidth for the more recent cards, especially once something capable of GTX 480/580 performance becomes affordable.
