Hello, Im going to build my first PC in a couple of weeks and since i have never built one before i really dont know what power supply i need for my setup, right now I have just guessed 700W but dont know if im right. My setup is:ASUS P8Z77-V LX Intel® Z77 ATX Motherboard - 1155 socket, Intel I5 3570K Processor, 8GB DDR3 (2 x 4GB) Corsair Vengeance LP Blue Memory, ASUS NVIDIA GeForce GTX 660TI Overclocked Edition PCI-E Graphics Card - 2 GB, Toshiba 1TB Hard Drive, Coolermaster Hyper 212 Evo AMD Socket AM2 AM2+ AM3 AM3+ FM1 Intel 775 1155 1156 1366 Processor Cooler and a Casecom 6788 All Black Case
Wattage is way over-rated for power supplies. Quality and amperage is what you need to be concerned with. As stated, a roughly a 500w (ar 40 amps or higher) will run that without problems.
What's more confusing is most power supplies will tell you a wattage rating and it's the total power deliverable by the 12v, 5v, and 3v rails. The good ones will tell you a wattage and it's the deliverable amount by just the 12v rail (the important one btw). Meaning that the latter example delivers a total power output well past the number of watts advertised. Only way to differentiate what's what is to compare amperage output with same-wattage units. Get something with 40 amps or higher and you should be set for most anything short of a high midrange SLI/crossfire GPU set up.