Watts on a PSU?

Question

PSU's price range can be very vast, with some upto £200+. But my question is what is the befit of a 1000watt(1kw) PSU or is a good 400watt PSU enough for the average PC. Pro's and Con's, whats your thoughts?

Answer 1

Most PCs don't use more than 200 watts at full load. A 400W PSU was useful in the days of the power-sucking smoke-belching Pentium 4, but computers in general are on a trend to run more efficiently. A good PSU will have 75-80% efficiency, so a 350W power supply is more than enough for almost anyone but overclockers and "hardcore" gamers (the upcoming Radeon X2900XTX will use up to 240 Watts on it's own). Just make sure to read the reviews for the PSU you choose because one that supplies unstable power can damage the components of your system.

Here's a useful power supply wattage calculator.
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Answer 2

It really depends what the pc is going to do and the hardware involved. Running a server that needs to be 100% reliable requires spending a lot on a power supply that won't fail. Desktop pc power supplies are still very reliable, but much cheaper however.

The main thing about power requirements is usually hype. People think more power = better, so manufacturers keep building more and more powerful supplies. But the bulk of this power goes unused in most computers. Unless you are running a massively overclocked P4 with dual high end graphics cards and a large number of hard drives in your case you will just end up paying more for your power supply than you need.

Most systems actually use very little power. For a normal desktop not set up for gaming I would get something like a Seasonic S12-430. These are cheap (about 40 quid), reliable and very quiet. If you have several hard disks or multiple graphics cards then maybe go for the 500 or 600W versions. Any more than this is silly - the supplies I mentioned will be overkill for almost any system.

You may well get several 'gamers' on here telling you more = better, but this is rubbish. If you want to find out how much power your pc draws from the mains you get can a power meter from Maplin that will tell you the power in from the wall socket.

Answer 3

You should know all about power supplies before you buy one, and then you should know all about the power connection requirements of your hardware before you buy. You know about watts but do you know about 20pin, 20+4, 24, dual rail, 6 pin and 8 pin and other connectors? Video cards now ask for 6 or 8 pin connectors for power. SATA hard drives need SATA power connectors if not IDE power. Motherboards need various power in various ways and combinations. Some power supplies provide stable power and some don't. 400 watts isn't always 400 watts! Be very cafeful. If you connect multiple drive in a chain, is the power supply going to guarantee dual rail 12v power to each drive? Will the PS peak at 400watts or stay constant at 400watts? Simply put, get a brand name power supply with dual rail support, and all the fan, video card, and 20/24 etc pin connectors that you researched your needs to be. The watts for a current gaming rig with two video cards, 4 ide drives, two sata drives blah blah should be as much as your wallet can handle but never below 400 watts (opinion) today.

Answer 4

400 watts if fine for almost all computers.

Some gamers buy $500 + video cards that may consume as much power as the PC. Serious gamers may need a 500 watt or larger power supply to power the high performance video cards.. Everyone else does not.

Answer 5

All components use power and they all add up, as you add more cards, or usb powered devices that usb actually powers.
4 sticks of memory can use 50 watts,
a p4 can use 40-100 watts, depending on the model.
There are a quite a few "power supply calculators" available to use.

Answer 6

I believe 1000 watts on an "average" computer is quite a bit of unnecessary overkill. However, if you plan to add a lot of goodies, External DVD burners, seem to draw a lot of power. 400 watts would be sufficient for you to be able to add several devices and I would not buy more than that unless you specifically had a compelling need for the extra power.