Solved About the power supply Tags: New Build Power Supplies HD Systems Product Last response: January 8, 2011 10:56 PM in Systems Share nihilite January 2, 2011 1:20:13 AM Can I get a 750watt psu if my system only require 400 at the moment because I dont have a power supply but plan on upgrading my HD 5670 to a 5770 then crossfiring a little after that. More about : power supply Best solution JackNaylorPE a c 139 ) Power supply January 2, 2011 1:46:10 AM A 750 watt PSU will operate at close to peak efficiency w/ a 400 watt load. I would note however that the 650 and 850 watters are the sweet spot for PSU's price wise. This 850 watter is a top end (10.0 performance rating on jonnyguru) and is only $109 .... the 750watter is $20 more ! http://www.newegg.com/Product/Product.aspx?Item=N82E168... Twin 5770's require only a 600 watt PSU however http://www.amd.com/us/products/desktop/graphics/ati-rad... in which case this 650 watter will do just fine http://www.newegg.com/Product/Product.aspx?Item=N82E168... Share nihilite January 2, 2011 2:01:18 AM Could you (or anyone else) explain what peak efficiency means psu wise? I read somewhere that its good to have 200w extra over head room. Kinda dumb but would a 850 watt draw 850 watts from the wall? Or only how much is required. m 0 l Can't find your answer ? Ask ! Get the answer nihilite January 8, 2011 10:56:34 PM Best answer selected by Nihilite. m 0 l Can't find your answer ? Ask ! Publish Related resources Solvedquestion about reputable power supply Forum SolvedQuestion about 250w Power Supply And new Graphics Card Forum SolvedLooking for a Power Supply for About $90 Forum SolvedQuestion about power supply Forum Solvedconfused about power supply for pc Forum Solvedfew questions about power supply Forum SolvedWorrie about Power Supply Forum SolvedShould I be worried about my new power supply? Forum SolvedOpinions, changes, and power supply wattage for my about to be built Gaming PC Forum SolvedNeed help About Power Supply And Graphics Card Forum Solvedask about Power supply Voltage Forum SolvedBuilding in FT-03 MINI and worried about power supply Forum Solvedconfused about power supply.. Forum SolvedPower supply about to die? Or something else... Forum SolvedFirst gaming build but concerned about power supply! Forum Solvedquestion about power supply Forum SolvedPower supply question about a PNY 9600GT Forum SolvedConfused about Power supply 12v rails Forum Solvedabout power supply Forum SolvedNeed Help About Power Supply Forum More resources Read discussions in other Systems categories Homebuilt New Build Prebuilt Cases Power Supplies RAM CyberPower !