PSU capacity?

[MidiGuy]

What do I need in terms of PSU capacity these days? We're building an AthlonXP 1800+.

Thanks!

-Midi

 

[BG4533]

A lot depends on how many drives and other things you have. A good 300W power supply should be enough for most computers. If you ever want to seriously upgrade it you may want to go larger. Can't hurt anything.

 

[elw00dblues]

BG 4533 has it right, at least 300 watts. But make sure that the PSU is from a reputable company also!! This can make the difference between stability and frequent inexplicable crashes. Companies like Enermax, Antec and PC Power & Cooling all make good PSUs, although they aren't the only ones.

 

[paralazarguer]

The above information is correct. If you would like to read a power supply guide which discusses calculating how much power you will need and what to look for in a power supply here's an articl that I wrote: article

 

[MidiGuy]

Thanks for your input about PSU output! :-D

Originally posted by: 7757524
The above information is correct. If you would like to read a power supply guide which discusses calculating how much power you will need and what to look for in a power supply here's an articl that I wrote: article

Thanks for the article! I was a little confused about one thing though - on that table in the article it looks (from the point of view of someone who doesn't know about this stuff) like combining the +5V and the +3.3V should come out to 196.2 (150 + 46.2). Could you please explain how this works?

Thanks!

-Midi

 

[paralazarguer]

"+5V- Before the Pentium 2, +5v was used to perform the function that +3.3v currently handles. The change was made to lower processor power consumption. This voltage is still used by the motherboard."

Basically, the 3.3 and 5 volt rails aren't going to be used seperately. It's just not possible with one type of processor. In the example provided you cannot simply add the maximum 5v and the maximum 3.3v to get your combined figure. Power supplies will provide a figue for the combined wattage which is the ammount of power it can provide to a device using either of these rails. Cheaper power supplies cheat by generating their total wattage figure by adding the 5v and 3.3v together. Since they can't be used simulatenously, this is wrong and the maximum combined must be used. In this example, the combined was 150. It's possible to have a combined of 150 and seperate numbers of 35a/16a instead of 30a/14. There is not a direct corolation.