EDIT: I assume you have all the 12v PSU / Motherboard ATX connections in place...
1st, let me tell you that your PSU is more than adequate for 4Ghz. So, before you run out and spend to replace it, let me mention a couple of things:
Its popular around here for people to claim you absolutely MUST have a single rail, 12V @ 30 amp plus PSU for a Presler.
I don't think that is always the case. In fact, I think the ONLY time you MAY need a single rail PSU is if you are super-cooling somehow, and are using very high Vcore (1.55 or more, IMO).
Within their current delivery capabilities, multi-rail PSUs have advantages, system-wide, over single-rail units. Thats the reason you see most of the higher-end commercial / enterprise type units going with this design.
That said, I can tell you that on my P5WD2-E, which is a fairly moderate system power requirement-wise:
(6600 GT video / 2 GB RAM / 1 SATA HDD / 2 DVD- R drives / 920 CPU)
Just to see, I tested a Antec SmartPower (low-end) 450 Watt (17 amps on 12v2 rail, only 15 on 12v1) and my Overclock was exactly the same as on my TPII 550 Antec (19 amps per 12v rail, better regulation, response time, etc..)
FWIW, my Presler OC specs are 1.385v, 4Ghz, and 1.4750v for 4.2Ghz. Either PSU produced same voltage / FSB curve.
You mention your memory is on "auto" and then you quote the timings. I'm not sure which you mean, but I would set the FSB you want (in your case 287), and then go into the memory divider and set it to a DDR value that is NOT overclocked for your particular memory. The DDR number will change when you change the FSB, right in the BIOS.
Then, go to the "chipset" page, and manually set slower timings (5-5-5-15, for example), and make certain that "hyperpath" is disabled.
Set your memory voltage at 1.9v, just to be safe, and your Vcore at around 1.425v for starters (may be able to ramp down, if its OK there - perfectly safe voltage at that level).
I'd run memtest 1st, but if you don't want to or don't have it, I would guess that the above settings should boot windows (could be a bit low on the Vcore, depending on your CPU) and let you do some stability testing to see where you are.
FWIW, just for giggles one time I put an unused Antec SmartPower 350 into my P5WD2-P system, with a 3.0Ghz prescott and it OC'd just fine to 4Ghz. That system had a very light-duty Vid. card, but did have an optical drive and a 4 drive RAID array.
I really expected that the system would be fine with that PSU, and it was. Fine in my case meaning 2xPrime stable for at least 24 hours, PCmark etc.......I really just wanted to remind myself that sometimes you have to mix in a bit of reason with all the hype you read. I did, however, put the bigger PSU back in after the test, though.
Good luck.
- Chris