I have a Thermaltake Toughpower 700w. I want to OC my Q6600 G0 to 3.2ghz and 2 ATI Radeon HD3870's as high as I can get them. Is 700w sufficient?

Along with those components I have a thermaltake V1 Cpu cooler, 2 Thermaltake Duorb gpu coolers, 4gigs of 1066 memory, x38 asus maximus formula, 1 hard drive, 1 disc drive, and 5 120mm fans.

No problem with 700w. I am overclocking my Q6600, ASUS Maximus Formula mobo, 4 gigs of DDR2 RAM and two 3870's using a Corsair 620w PSU. I also have two SATA DVD burners, two SATA HD's and 5 fans. Watts are not an issue... heat is.

I was getting high core temps (greater than 75 celsius) on my CPU under load running 350 x 9 at apx. 1.35 Vcore, but everything was running OK. I backed off on the volts and FSB to 333 x 9 at 1.25 (plus or minus .03) to get my temps down below 70 degrees. I am considering lapping the CPU and the Ultima90 cooler to lower temps hopefully by another 5-8 degrees - already bought the 400 and 1200 grit paper, but I need to take a break from pulling apart my rig.

Hey Nurn ... I think I got the exact same setup as you ... nice rig.

700 is plenty.

I had my rig working, only with one HD3870 mind you, and an enermax 350 watt.

650-700 watts will work for a short/medium term (0-3 years) time with the newer quad core processors. However, with the degredation of the PSU, 700 watts is the borderline you would want for long term use (5+ years). It would depend on how hard you push the new PSU. If you push it hard and pull more than 80% load for long periods, then it probably won't last 5 years.