PSU question.Follow

I use strictly Thermaltakes and have nothing but good things to say about them.

When you talk power supplies, there are a couple different things to keep in mind. The first and foremost will be what you intend to do with your computer. If you will only ever be running a single video card in your computer, there is no reason to go above 65-700 watts. If you only will ever run 2 video cards at a maximum, 850 - 900 should be your target. If you think you might realistically run 3 video cards during the lifespan of your power supply, then you should be looking at a 1,000 or more watt PSU.

The reason you want to size your power supply appropriatly is that the more wattage your power supply is capable of delivering, the larger the internal components tend to be, which tends to result in more heat production and more energy usage even if you aren't using that full capacity. The upside is that the power supplies with higher end components tend to last longer. Many of the higher end units also have better protection and monitoring circuits built in. Putting a 1,000 watt PSU in a computer that will only ever run 600 watt worth of equipment will add about $3-$5 to every power bill for the life of your power supply for example.

Rail designs in power supplies tend to go in waves. For a while multiple rails will be the big thing, then they will go back to fewer, but much more robust rails. The number of rails you have really doesn't matter though, because the power supply will still go into failure mode if one of them cooks. There are very few "bad" designs. Most of the bad power supplies you run into are cheap chinese or india produced knockoff power supplies. The problem with them in particular is they tend to put a 600 watt rating sticker on a 350 watt power supply design. The power supply has to be built to deliver 350 watts under normal conditions, but also under peak demand. Most of the more expensive power supplies are usually under rated for that reason.

The real key thing to look at these days is efficiency rating and warranty. A higher efficiency power supply not only saves you money, it produces less heat and thus creates less load on your cooling system. You will see stickers for 80+ efficiency, with different ratings. the higher the "metal" color, the more efficient the power supply has been certified. Gold is better than silver, etc. If you can get a high efficiency power supply with a lifetime warranty that covers computer component damage in the event of failure, you are in the right place.

Antec and Thermaltake both make decent power supplies. Corsair and Cooler Master are also worth looking at, but my personal brand of choice is Enermax. They are in all my personal computers. I tend to use alot of antec ones at other work, because they are very cost effective, but the Enermax ones are just the best ones available. The current top of the line Enermax design at the moment is the Maxrevolution 1,000 watt unit: http://www.enermax.com/home.php?fn=eng/product_a1_1_1&lv0=1&lv1=58&no=190

They do make 1,200 watt PSU's from time to time, but anyone who is going with a quad GPU setup is probably going to run two PSU's anyways so they really don't tend to sell very well. I have the previous revision of that particular power supply. It looks like they have gone down to a 5 year warranty now, which is annoying, but still not bad compared to the 1 year of antec.

The GPU power requirement rating on your video card is for total system available wattage. For example, a Nvidia Geforce 590 GTX dual card requires a 650 watt power supply in the system. Of that, the card itself only uses about 300 watts of that. Another 150-200 is the CPU itself, the drives each use about 100 watts, the motherboard uses another 100 or so, etc. ATI cards tend to use less.

If you want to outline your system hardware (specifically how many cards, how many and what type optical and hard disk drives, what motherboard and processor, how many fans, etc) here along with your future upgrade plans for this present computer, we can probably give you a better idea of what you are going to want.

For a two GPU system, an 850-900 watt PSU is going to be more than adequate, 1000 watts at the outside. you aren't running or planning to run enough hard drives to impact your power reserves significantly, and the amount of fans and optical drives is well within normal.

You can certanly still upgrade if you want, and going with a higher end PSU will tend to extend the life of your system, but that money might be better spent towards a solid state hard drive or a second 570.