
The Coolbits is the simplest way, it just enables an otherwise hidden control panel in the standard Display Properties - Advanced area. There are plenty of options out there though.

O/C like you o/c anything, use steady steps and test thoroughly at each step looking for visual defects as well as the usual crashing etc. When you find defects or instability then it is best to back down a couple of steps, don't forget to try both RAM and the core. I would rec stepping up the RAM speed first and see where that gets to, and then raise the core. You should get from 250/444 to around 300/550 with the usual 4.0ns RAM, if you have faster RAM like 3.6ns then you can expect 300/620! As a guide to perf, 4400=275/550 and 4600=300/650, a 4200 at 275/550 will give identical perf to a GF4TI4400. You can check what RAM ns you have by reading it directly from the RAM chips, 2nd line down last 2 numbers.

HTH!