need more info.
First what Motherbord you running.
What ram are you running.
What Sort of cooling you running . Heat sink and fan or water cooling. this will give us a batter idear on how to proceed.
All so the Q6600 go has been over clocked by many users on here and much of what you are after has all ready been talked about. You can use the search feature above to look for most of you answers.
How ever a q6600 is optimal at 3.6 ghz at 3.8 ghz its fast but youll not see any speed difference unless its for bench testing. I think on Air cooling people mange to get around 3.2 Ghz with out heating problems.
You need to find you ram timings for you ram and input these direcly into the bios such as 5 5 5 15 and then set you voltage of your ram. If you do not know you ram timings you can download CPUID from here -> http://www.cpuid.com/cpuz.php
and this will tell you what they should be set to.
Allso this gives you info on you CPU speed and motherbord. You can then take screen shots of this program and we can help you out.
Allso a nother good tool is HW Moniter from there site here -> http://www.cpuid.com/hwmonitor.php
This will help you keep an eye on the temps.
here is a over clock on a 6600 Go with water cooling
this is a 4.* Ghz over clock on water cooling. you can see the ammount the V-Core was raised to as well and the ram speed.