Right sorry for taking so long, I've been reading vigorously and I've come up with some settings for a 3GHz overclock.
You might notice that I haven't defined settings for other options and well that's because you can leave them as they are as these ones are the main ones to set. When you set these settings if your bios has a save profile function use it so you don't have to re-enter all the settings incase you need to clear your cmos due to the system not booting. Although with ASUS boards and I'm pretty sure your one has this, when the system fails to boot/POST it turns off (or you can turn it off it doesn't) then when started up the next time it runs at stock settings but remembers your bios settings so you can adjust.
Anyway set the settings below and then if the PC boots up great! Go into bios and just check how the CPU temp is. My Q6600 idled at 40c or so at a 3.6GHz. Now if the temps are okay to you exit the bios and proceed to booting to Windows. If theres a crash or a BSOD then it's unstable then put the settings back to stock (Save stock settings into a mobo profile too if you can) and then come back and post here. I don't think you'll BSOD but you never know. If you do manage to get into Windows then make sure you have a few tools/utils for testing your overclock.
CPU-Z
CoreTemp or
RealTemp
Prime95 x32 or
Prime95 x64
HCI Memtest
Memtest86+
CrystalCPUID
Some of those tools you might not need (if you get a stable overclock quick) but get them anyway.
The first one you'll be using is Prime95 + CoreTemp/RealTemp + CPU-Z.
When you run Prime95 for the first time click right button (iirc) which says just stress testing. Then click the menubar and goto Advanced then tick Round off checking. That makes sure errors are detected and you'll see the Prime95 systray icon go red.
Now open CPU-Z too and check that your CPU speed is 3GHz and FSB should be 1333MHz (Add 1 more MHz to your FSB in bios for 1337MHz FSB :haha

. Also note that your Core Voltage in CPU-Z is probably a bit lower than what you set it as in BIOS. It's always like this and if you didn't enable LLC (Load Line Calibration) then it'd drop quite a bit when you put it under load. That's called VDroop and it's always best to minimize it.
In CoreTemp or RealTemp you can choose to have it log temperatures to a file just incase the PC shutsdown you can always go back and read what the last temperature was.
Once you have those 3 open goto Prime95 and click Options from the menubar and click torture test and it will bring up an choice box.
What I do is run Blend and then In-place large FFTs. I usually run each test for around an hour each because I try to find my max stable overclock, but if you've already got a set and feasible overclock chosen (Like 3GHz) then you can do a full run. I run it for around 6h-8h (overnight when I'm sleeping) so if you're sticking with 3GHz then do that. If you get it stable at that and want to try for higher then I'll help you with that later.
Anyway just start a blend test and watch the temp monitoring program. I don't let my cores go over 65c but the
Intel Processor Spec Finder
says 71c is their limit. So within a minute or two the the CPU temp will settle a bit and not increase so much and if those temps are decent and you're happy with them you can leave Prime95 to keep testing. If the temps get a bit too hot for your liking then click Test from the menubar and choose stop or alternatively right click the Prime95 tray icon and choose stop.
I've gone on quite a few forums to see the voltages for certain Q6600 overclocks to get a general idea rather than starting from scratch trial and erroring it.
Anyway my hands are hurting here are the settings, you know what to do and if you don't ask me more questions before you go ahead and change your bios :wavey: