Two methods....

Method #1: BSEL mod...



Picture is explanatory....


Method #2: Thru BIOS overclock settings....

1. Set system bus frequency to 333MHz. You may need to boost the FSB voltage a bit if not stable..

2. Set Memory Multiplier to 2x, your RAM frequency should be around 667MHz (safety). If you are adventurous, then try setting Multiplier to 2.5x, your memory frequency should be around 832MHz (slightly higher than rated frequency of DDR2-800, not sure if your RAM can handle or not... may need to increase RAM voltage a bit)

Make sure you run Memtest to test for RAM stability first...

Anyway, make sure you also have a good 3rd party cooler to keep the CPU heat down..