Well, first thing is first. Get into your BIOS. Q9300's don't OC all that well as they have a very low multiplier (7.5 max). Make sure the multiplier is that high for best effect. If you can't get 7.5 and are instead getting 7, there is an option called "n/2 multiplier" or something to that effect, just enable it. Now go find C1E, EIST, Speedstep, and Thermal Management control, and disable all of them.
To figure out what your chip is truly capable of, we're going to max out the voltage and keep amping up the FSB until it crashes. Put your vcore (or CPU voltage) to 1.35V DO NOT GO OVER THIS VALUE, YOU WILL DESTROY YOUR CHIP. Make your RAM voltage 2.1V, and your northbridge voltage 1.3V (it can be slightly higher if you can't get it exactly there). Make your Dominators run at a 1:1 ratio with your FSB, should be called "400/800" in your options.
Now, crank up the FSB to 425, your board should be able to handle it, but we don't know about the chip yet. Boot up.
If your PC doesn't turn on, doesn't make a single, short beep, and/or doesn't boot into Windows, the OC is too high for the chip. Turn off the PC and reset the CMOS by taking out the battery (looks like a shiny nickel on the motherboard) and put it back in after 30 seconds.
If you boot, download CPU-Z
, Real Temp
, and Orthos
. Boot up CPU-Z and make sure your voltages and speeds are what they should be, etc. Look at Real Temp, you idles should be in the 30'sC. Select "Small FFTs" in Orthos and let it rip. Monitor your temps closely for the first 10 minutes, if they get into the high 60'sC you're in trouble...stop it if it does and bump down to 400FSB instead and retry. If your temps are manageable, let it run for a good 4 hours or so. After that, you can decide if you want to go for an even higher OC, or keep the one you have, because you're now stable
I hope this helps, good luck!