More than one PSU in the same box

[Berlin0430Hours]

Hi,

Yes I know what it may sound like.... :lol:

Is it possible to use two smaller power supplies for my new SLI system instead of one big one? I've already got a 400W and a 300W so instead of buying a new 550W or 600W PSU I want to put both these PSU's in my box.

Thanks

 

[sailer]

Possible, yes, but not advisable. Its not just the total wts that you're looking for, but the amount of amps across the 12 volt rail. If there's not at least 18 amps, the video cards may not power up correctly

 

[doolittle]

if you're handy with a dremel and soldering iron it will work just fine. I did the same thing a while back when I had a weak 250w ATX and a spare 250w AT laying around:

I just reduced the length of the AT power cable and stuck an old DPST rocker where the cable used to be. I assume you have two ATX units so you'll have to extend the green "power_good" or "ps_on" signal (pin 14 on 20-pin and pin 16 on 24-pin, and maybe the adjacent ground wire) on both of the PSUs for synced' power on.

Don't forget to keep the outputs independant per-psu since you definitly don't want to share those - I hooked my secondary psu up to the gpu power connector on my 9800 pro and all the hdd / cd / dvd drives since I had 6 hdds and both opticals.

 

[Berlin0430Hours]

Thanks for the info.

The 400W PSU (Chieftec) has got 14A on the +12V1 rail and 15A on the +12V2, so I assume 29A in total. The 300W (FSP Group Inc) has got 13A on the +12V rail.

I haven't bought the SLI stuff yet, but this is what I've got in mind:

AMD AM2 X2 5000+ (or else 4200+)
Asus M2N-SLI Deluxe
Transcend 2x512MB DDR2-800
7800GTX (I've got one already)
Western Digital 320GB SATAII HDD

According to the PSU calculator I will need around 530W of power.