View Full Version : Don't gang multiple PSUs together to work SLI

06-25-05, 04:48 AM
A friend working at NVIDIA warned me today against using separate low-wattage PSUs on each video card to achieve sufficient power to run SLI (as a poor-man's alternative to one large-wattage power supply). This fellow suggested that out-of-phase power could fry your SLI video cards!

06-25-05, 07:46 AM
lol, i wouldn't have the nuts to try something like that.... good to know though

06-25-05, 11:38 AM
I don't know i was kinda tempted to get two fan less PSU's Antec.

06-26-05, 01:15 AM
Well, I was saved at the last minute. :eek:

In 2003 I had successfully tested a 5800 Ultra on a separate power supply than the motherboard and drives; the pair benched significantly (16%) higher than my most powerful single PSU.

06-27-05, 01:03 AM
some server boards allow for dual or redundant power supplies. so i guess it has to have the proper cuircutry to do this .... sli2 maybe ?......

06-27-05, 01:04 AM
Hm, i did this with a systme once, one psu on mobo/rest one on my 6800 ultra i guess i got lucky

Pandora's Box
06-27-05, 01:29 AM
i can see where the nvidia fellow is coming from. though i guess you could do one big psu for the cards and then a smaller one for the system...

06-27-05, 01:40 AM
Doing that kinda thing is pretty dangerous anyways. When it comes to providing power to anything, you ALWAYS want to follow the norm, unless you have like a bachelors degree in electrical engineering and really really know what you are doing. Sometimes resistance and impedance can come into play in odd situations where you least expect it, and you'll damage things.

06-27-05, 12:11 PM
How can DC be out of "phase"? I thoughtknow that only AC (and AC like) voltage can get out of phase.


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