Hey Mercurial,
I got the same rig as yours just the E6750 - 2.66GHz, im running it at 3.2GHz with no problem, even with the stock cooler it is running at about 39 degrees under full load.
This is what i did:
1. Download the latest bios so your G0 stepping will be supported. (My P5K needed the bios updated)
2. Go to "Jumper free configuration":
2.1 set OC to "manual"
2.2 set fsb as 400Mhz (remember, FSB of mobo is quad pumped so you are actually at 1600Mhz, your memory is run at double data rate, so if your fsb is 400MHz your memory is running at 800MHz)
2.3 set cpu multiplier as 8 (this will give you an OC to 3.2GHz, 400Mhz*8=3200MHz=3.2GHz)
2.4 save and exit
2.5 Boot XP and watch the temps of your mobo and CPU carefully
If you do the above, your pc will run at about 2.4GHz during idle as the CPU multiplier is pulled down to 6 (400Mhz*6=2400MHz=2.4GHz), but when under load, it jumps to 8 and you are running at 3.2GHz. If you always want to run at 3.2Ghz, then disable EIST and C1E in the bios, this will stop the multiplier from being lowered. Use a program like CPU-Z to see your current CPU frequency.
To OC more, increase the FSB frequency, just make sure you dont run your CPU and mobo too hot. After an OC, run a benchmark and see that it runs stable. If it is unstable, decrease the fsb frequency.
To get a indication of what kind of fsb speed your mobo can handle, you can set the multiplier lower and then increase the fsb frequency until it becomes unstable or too hot.
Remember, that overclocking can damage your PC if you are not careful!
Dont come crying to me if you blow something.