some ppl had trouble with the p5b-deluxe and 2.1v ram, but my HZ's booted up just fine on my p5b-deluxe (still had the 0504 bios).
If it doesn't boot up for you, then just go to bestbuy or something and get a cheap stick off ddr2 ram and set it with that, and take it back when your done. Remember to update the bios though (i think asus realized this problem a while back and have fixed it with updated bios). So if you oc it and have to reset it, it won't reset back to the under voltage.