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.
CPU: e6600 @ 3.2ghz
RAM: 2GB G.Skill HZ PC6400
Mobo: ASUS P5B Deluxe
GPU: Sapphire HD4870
Soundcard: Creative Labs X-Fi XtremeGamer Fatal1ty
HDDs: 250GB WD + 750GB WD + 2x1TB WD
Monitor: Samsung 226BW
PSU: OCZ GameXStream 600W
Case: Cooler Master Stacker
OS: XP Professional SP3
Mouse/keyboard: Logitech MX518/Saitek Eclipse II
Speakers: Logitech Z-2300