I would say it depends on your PS. What is its efficiency? Post all the info off of the sticker on the side of the PS Is it a 400watt Peak Power rated or a 400w Continuous power rated supply? For instance: * PSU A has a peak rating of 550 watts at 25°C, with 25 amps (300 W) on the 12 volt line, and * PSU B has a continuous rating of 450 watts at 40°C, with 33 amps (400 W) on the 12 volt line. ^^ stole from wikipedia PSU B is obviously better.
Here is my actual watts usage at the socket for my pc. Exact wattage gain by use of a Kill A Watt meter in between the socket and my power cable. Exact hardware specs when measurement taken: Abit Ab9 Pro MB Intel Q6600 quad core - G0 stepping (currently @ stock 2.4ghz) 8GB (2GBx4)OCZ DDR2800 OCZ Reaper HPC memory ( currently @ stock speed) 1 Ati HD4670 1GB DDR3 PCI express 2.0 x16 (Gigabyte) video card 4 Western Digital Enterprise (RE2 Series) SATA2 hard drives (RAID5) 1 Western Digital Caviar SATA2 hard drive (paging & temp) 1 CDR/DVDRW drive 1 Floppy/Multi-Card reader running off USB2 headers 1 92mm CPU fan 2 120mm case fans Antec EarthWatts 500W Continuous power (80-85% Efficient) power supply System Idle (5 min after boot) = 165-170 watts System under 100% GPU load (FurMark) = 200 watts System under 100% CPU load (Prime95-all cores) = 210 watts System under 100% GPU and 100% CPU load (Furmark + Prime95) = 250 watts My systems estimated watt usage per eXtreme Power Supply Calculator (lite): Recommended PSU wattage = 381 watts Not too bad of an estimate My system could probably run on an efficient 400W or very high efficient 350W if I wanted to straddle the fence Just thought I would let everyone know in case you were wondering how close that estimating tool is if you are precise in what you put in as your actual hardware. late
Yeah, mine was 583 in that calculator. But it still doesn't take into account the power losses and other devices that may draw power from your psu. I guess that estimate is pretty close, but I'd say add another 50-75 watts to be a bit closer to your real power consumption. So 583 with all devices I had hooked up, according to this calculator, but a high output OCZ 600W PSU of about $250 isn't sufficient. Had to eliminate stuff, and now it's doing fine again with a 500gb drive less, and minus 2 pci cards. Consumption now is 512 watts.