View Full Version : Can I use a 300w power supply with a P4?

04-19-03, 08:45 PM
was wondering if I absolutly had to get a 400 watt power supply in order to run a P4, or could I use the 300 watt that I have for my Athlon? If so, what's a decent cheap one?

04-19-03, 09:38 PM
looking at this article could maybe shed some light on the
your current CPU should draw about 6.5 or so Amps on the
12+rail, a P4 is a bit higher ranging from 8-10..
Look at the table on the side of the PSU, it should say
how many amps there is on the +12 rail.
Around 18A sounds like sufficient for the P4 maybe..
If its around 10A I would recommend a new PSU..

Also its not 100% that you have the necessary connectors
on the PSU, think the P4 requires a certain cable from the
PSU to the mobo near the CPU.

You could try the old one, if it runs unstable its a good
chance its too weak.
Maybe there is risk of damaging your comp tho?

Toms hardware has a pretty big review on PSUs

04-20-03, 12:31 AM
I run a 300 Watter.

04-20-03, 08:56 AM
Holy crap Lunar.... thats a hell of a comp to be running on 300W.

Guess that means I wont need to replace my 300W for a while :)

04-20-03, 09:26 AM
If he has 22A on his +12 rail
and you have 10A om yours you prolly
wont run stable on yours..

It varys alot, generic PSUs are often worse..

More on this:

04-20-03, 05:38 PM
Better quality p/s are the best bet-I have used Antec/PC Power & Cooling and Enermax. I would get a p/s over 400W it will be good when you have a number of HD's, etc., and don't forget that power plug into the NV-30/35 and ATI 9700/9800 series cards.

Always good to play it safe, a cheap supply can = an major "Humpty-Dumpty" that you cannot put back together again:)