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Running dual PSUs?

D

dboy

Limp Gawd
Joined
Mar 24, 2003
Messages
189
Putting together a bitcoin rig out of some random parts I've got around.... not sure on the mobo/cpu yet (possibly a socket 1155 celeron, possibly a Q6600). Plan to run a 7850 and a pair of 5870 GPUs in it.

The 5870s are said to draw close to 200w at full load. The 7850 is less - I have on in my current machine and it's around 110w overclocked.

So I'm looking at 500W+ on GPUs, plus the rest of the machine.

Currently have a 600w PSU in the case (don't remember model, but it might be a couple years old). Also have a Antec Neo Eco 620W sitting new in the box.

Is my best bet (and in this case, cheapest is a very high consideration) to run dual PSUs to power all the cards? I think the 5870s each use a pair of 6 pin plugs and the 7850 uses a single. Each of my PSUs has 2, so I'd need to use an adapter from some molexes to run the 5th plug.

This is going in a 4U rackmount case, so I know I've got space to stick the extra PSU inside. Do I need to do anything other than get one of the dual-psu adapter cables so that they both come on together and then go from there? Make any differnce how I divide up the load? I'm thinking the new antec PSU is the better one, so I'd probably run the machine (mobo, hd, etc) and one 5870 off it, and then run the second 5870 and the 7850 off the second PSU.

Or is all this overkill and I can squeeze it all out of the antec? I don't think that's a good idea, but you all know better than I :)
 
The SXS is a decent unit, so you should be fine just getting one of those adapters.

I would split the load as evenly as possible, with more bias towards the Antec.
 
Thanks - now gotta get a dual-psu adapter or make one. can't find them on microcenter's web site, but gotta go there soon anyway so I'll see if they carry them.
 
After playing around with how to put both PSUs in my case last night, it actually fits pretty well. Case is a 4U rackmount I got free from work. I don't need an optical drives in this, so by removing those, the 5.25" bays up front fit a PSU with most of the cables bundled up nicely.

I'm actually thinking about going cheap here and skipping the dual psu adapter for now. This won't be turned on and off often, so I might just hang the 24 pin plug out the front (there's no panel to replace the missing optical drive, so a gaping hole there anyway, but it's behind a door so unseen unless you're turning the machine on anyway!) and use the paperclip trick to turn on the second PSU. Saves $15, which is a significant % of the build cost on this since most parts are extras lying around :)
 
If you're good with wires and electrical stuff, you can splice the green motherboard wires together. If not, yeah, it would be better to do an adapter. However, you want to synchronize the turning on as much as possible.
 
Yeah, I probably oughta splice it. Gotta connect green AND a black though, right? The splicing is no problem, I've done plenty of wiring. Just trying to be cheap and lazy :)
 
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