These are the settings I'm using for 450, and what I needed to get to 480FSB, but keep in mind I have a quad, so they may not work the same for you. If you shoot for the high side, and get it stable I suggest you try reducing the voltages and see how low you can go and maintain stability.
CPU Voltage: 1.5125v (anything lower gave me core failures after 1.5-2hrs. 1.6v allowed 3.8GHz, but I think a little more is needed for P95.4 stability)
CPU Voltage Reference: 0.63x (I wasn't getting much over 3.2GHz until I changed this from Auto. 0.57x, and 0.59x wasn't stable. 0.61x worked, but I have a feeling 0.63x is best.)
CPU Voltage Damper: Enabled
CPU PLL Voltage: 1.70 (I may be able to reduce this to 1.5 for 450FSB. At 480FSB 1.5-1.6 [or 1.7?] wasn't stable, 1.8-2.2 worked.)
DRAM Voltage: 2.3 (2.2 may be fine. I just wanted to ensure stability through testing. I'd like to know how high I can safely put this to possibly get tighter timings, or 1125 @ 5-5-5-15 to work)
FSB Termination Voltage: 1.40 (1.5 for 480FSB, I may be able to go lower at 450)
North Bridge Voltage: 1.55 (1.95 for 480, anything higher is actually worse)
North Bridge Voltage Reference: AUTO (0.67x for 480FSB, auto seems to work best for 450)
South Bridge Voltage: 1.20 (may be able to turn this down)
Once you get the FSB stable go back and increase your multi to 8, and keep giving it more Vcore until you are stable.