First of all, whoever gave you a "ZOTAC GeForce GTX 480 AMP video card", you have a great friend there
Looking at hardware, your looking at a 650watt power supply, although I see references to 450 watts being minimum. Its always better to have adequate wattage than to be running the PSU at 100% and burn it out, or have to buy a heavier duty PSU later when you add or upgrade further down the road. A 650 watt should be plenty for now and give you many years of good service. *Although I would buy a power supply from a well known and respected name brand as for some that claim to be for example what happened to me ... 500 watts are barely able to handle even a 300 watt load such as this linked PSU from Golden Power that came bundled in a cheap computer case
http://sohoo2008.en.made-in-china.com/product/veFxHiwALIWM/China-8cm-Lower-End-Power-Supply-ATX-500-.htmlCorsair, Thermaltake, and XFX are good brands ..... while Antec, Coolmax, Diablotek are hit and miss and I usually look at the feedback of these brands in relation to a specific power supply before buying. They have had good and bad batches through the years.
I am currently using a Coolmax in my gaming system which was rated 4.5 of 5 stars and like 68 feedbacks when I placed my order to buy it inexpensively, but its only a 460 watt because I am running AM3 Athlon II x4 620 2.6Ghz with 4GB DDR2 800Mhz Corsair XMS2 RAM, with a low cost $30 video card, but pretty well performance ASUS AMD ATI Radeon 5450HD with 1GB DDR3 which is not power hungry like higher end cards. This is not to suggest going with Coolmax, if I wasnt so cheap, I'd rather have a Corsair, Thermaltake, or XFX PSU and should have spent more than $25. But this PSU was cheap and has been reliable for over a year now of daily gaming.
