Power Requirements. Help plz.

Sorry to pester you lot again, but any chance u can take a guess at what psu/wattage i'll need for my system. Might help me save a little money, which would be nice.

Gigabyte GA-48X-DQ6, Intel Duo E8500 3.16GHz dual crossfired HD 4870's, OCZ 4GB (2x2GB) ddr2 ram, 2x Samsung SpinPoint F1 750GB SATA-II 32MB Cache, Westen Digital VelocilRaptor 150GB 10000RPM SATA-II 16 MB Cache, Antec Twelve Hundred Ultamate gaming case. I don't know what soundcard im getting, but will be something cheap and i may have to add 1 or 2 other peripherals. Oh and dvd rom + Dvd-RW.

480w for peaked 4870 crossfired and i think E8500 overclocked is around 100w, so thats already 580w. I don't know how much the m/b, ram, hdd's and peripherals would all use up and i hear it's good to have power to spare so a system runs without any hicupps. Im taking a guess that it' somewhere between 750-850w needed. Can anyone comfirm plz.

Thanks alot!

I entered in my specs, pushed the tdp to 90% and the system load to 95%. Then overclocked my cpu to 3.8GHz with voltage 1.35 and finally add capacitor againg 30% to account for 24/7 usage for 1 year+. It's given me around 747w, so im estimating that 750-800w will be plenty to cover my system for over a year or more.

With extreme psu calculator you can take away about 50W because my specs right now, said i need 450W and ive been running it with a 350W for a year.Helbrec

D: ive done that with my 6600GT .. 4 years later it was fried :( good thing it was about time to upgrade