The biggest hurdle people seem to trip up on is that on Intel chipsets the Front Side Buss and Memory speeds are linked. So when you increase the FSB, you are *also* forcing your RAM to run faster. Now... A Q6600 will take a 30% overclock on air cooling, no problem. Memory??? Do Not Count On It. Not At All. So before you start, set the memory divider (ratio of memory speed to FSB - it has different names in different Bios')
so your RAM is UNDER
clocked. This way when you increase the FSB to overclock your processor, you'll have headroom.
Important detail: Front Side Buss speeds are 4 operations per base clock. This means your 1066 stock speed is actually 266 x 4. Memory speeds are on multiples of 2 - So DDR2 800 is actually 400 x 2. As long as you take this into consideration and don't overclock your RAM, you won't go too far wrong.
In your case, you have DDR2 800 RAM. So as long as your motherboard will allow it, you could increase your Front Side Buss from 1066 to 1600 (400 x 4), run your memory on a 1:1 ratio with the FSB (400 x 2 = 800) and not break any rules. So far so good....
The third piece of information is that your processor has a multiplier as well. In the case of a Q6600, that is 9. Intel "Extreme" processors (the US $1,200 ones) have an "unlocked" multiplier - this means you can increase it. A Q66 does not let you do that, but you can DEcrease it, if you want. Now: Remember the baseline speed for a 1066 FSB is 266 Mhz. 266 x 9 = 2,394, and so now you know why your processor is running at 2.4Ghz. SO!! 400 x 9 is 3.6Ghz - Doable with good aftermarket componentry, but aggressive for air cooling. And I certainly wouldn't recommend it on the stock Intel Heat Sink/Fan. (more on this next paragraph) So, you have two choices - go with a lower Front Side Buss: 333 x 4 = 1333, 333 x 9 = 2997 (3Ghz), and 333 x 2 = DDR2 667 Memory at 1:1. Or lower the multiplier on the processor in order to run your Front Side Buss and memory harder while not pushing your processor as much: 400 x 4 = 1600 FSB, 400 x 8 = 3.2Ghz, and 400 x 2 = DDR2 800 at 1:1.
Regarding heat: As you push your components harder, they will generate more heat. Also, increases in voltages needed for more aggressive overclocks will increase heat output nearly exponentially. This is why some of the very serious overclocking people will use liquid and even some exotic methods (phase, liquid NO2, and all sorts of craziness).
Your stock CPU cooler is meant for just that: stock speeds/voltages.
My general experience with a Q6600 is you can have 3.0 Ghz with no more effort than simply setting the front side buss to run at 333 (1333Mhz). Seldom will voltage changes be needed. With a little care, a mild (10th and a little) bump in voltage, and a decent HSF ("Heat Sink/Fan") you can get to 3.4 without much trouble. 3.6 is more aggressive and will need a bit more power and will definitely need good cooling. Also - If you're running air cooling, take the ambient temps into account. If the room is 10 degrees warmer, than your processor will also. No Free Lunch.
Since this is an OS Specific site, I'll post a link to the Core 2 Duo/Quad Overclocking guide at Tom's Hardware: http://www.tomshardware.com/forum/24...ds-duals-guide
Apologies if this is bending the rules a bit, but that's a lot of information to relay...