Originally Posted by Arxontas
The OP has got a 65nm Kentsfield not a 45nm Yorkfield.
The difference between an overclocked Yorkfield (4 Ghz) and a 4770k isn't huge. It's, in fact, 99% the same.
I should know as I went from QX9650@4GHz to a 4770k.
If you read the article you quoted, you will see how well the Yorkfields perform.
In the OP's case however, he will see a substantial improvement, as the Q6600 was significantly slower and overclocked a lot less.
I know that he does and the yorkfield is newer and runs cooler and is slightly faster clock for clock as I mentioned, and yes it's OC'ed further, but I linked it because it gives a good ballpark comparison to a modern CPU!
Also in everyday task a core 2 quad is more than enough and should feel the same, most people shouldn't notice the difference. And as you stated, yes the core 2 quad is still a viable gaming option as shown in their q9550 keeping up, but my point was that cpu is better than what he has now and upgrading it would net him a pretty noticeable upgrade, and on to my main point that the biggest change he will see is if he upgraded the graphics card first! Even if it was bottlenecked it would an upgrade is still an upgrade, and he can look at replacing his CPU, RAM, and Motherboard, and re installing windows, if he had to replace his q6600, so the GPU is a no hassle, and noticeable upgrade