I recommend and currently use the EVGA 500B 500W Bronze Power Supply. It’s 80 Plus Bronze certified which means it’s at least 80% efficient, wasting no more than 20% electric energy. It has a single +12V rail which delivers 40 amps. The unit uses a 120 mm fan for cooling and I find it to be fairly quiet. With 500W of power and 40 amps on the +12V rail, it should do the job for most gamers that have computers with only one video card. The EVGA 500B delivers reliable, stable power and is available at a great price. EVGA also offers 80 Plus Bronze power supplies in other wattages (550W, 600W, 650W, etc).