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 108 ) 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... 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. Can't find your answer ? Ask ! Get the answer nihilite January 8, 2011 10:56:34 PM Best answer selected by Nihilite. Can't find your answer ? Ask ! Publish Related resources: ForumQuestion about current Power Supply ForumQuestion about power supply and overclock ForumQuick Question About My Power Supply ForumConfused about the capabilities of power supply ForumAbout GTX 650 and Power Supply ForumPower supply questions about GTX 680 SLI ForumUpgrading my power supply .. confused about the size ForumCuriosity about my Power Supply ForumQuestion about Power Supply ForumA question about a power supply and motherboard. ForumOpinion about cheap power supply and socialization ForumQuestion about mini-pc external power supply ForumBought a pc question about power supply and overclocking ForumQuestion about power supply ForumQuestions about putting a power supply outside the pc's case ForumQuestion about a power supply ForumQuestion about modular power supply ForumAbout Power Supply ForumQuestion about SLI & Power Supply . ForumNot sure about power supply More resources Read discussions in other Systems categories Homebuilt New Build Prebuilt Cases Power Supplies RAM CyberPower !