I've just been on ebay looking at new PCs and or components just looking for what sort of price I should be spending for different components for my system. One of the things Im looking to is a PSU. I put my information into this tool http://www.extreme.outervision.com/PSUEngine It came up with a 515Watt PSU required for the system I am trying to build. So naturally I went looking for a PSU to fulfill this for me. I saw this one http://www.ebuyer.com/UK/product/124927/rb/0 its marked as 700w and pretty cheap. I also saw this one http://www.overclockers.co.uk/showproduct.php?prodid=CA-044-AN&groupid=701&catid=123&subcat=103 its marked as 430w and quite alot more expensive than the 1st PSU. Im confused. I got some questions 1. I read a article on how to choose a PSU, it talks about the 12v rail being the most important part rather than the actual wattage, how do I find this out? 2. If you had a system that required 515watts of power, and you had $80 what PSU would you comeback with? 3. Why is the Antec 430w PSU more expensive than the 700w Generic PSU, what does it offer that the other one doesnt? And same question as above here too if you had a 515watt system which one of these PSUs would you choose if any? Hope this wasn't too stupid a question Necrosjef.