I have the 420N. If you upgrade to the newer BIOS, you can adjust the multiplier if the CPU is unlocked. Not the best o/cing board since the FSB/DDR/AGP timings are all tied together (there are like 22 different combinations of timings that you can use). I've gotten mine up to 147MHz for the FSB (about 290 or so for DDR) on a 1800+ and 2 sticks of Corsair DDR, and it runs fine. I'm going to unlock my CPU later.