Multiple motherboards off one PSU?

A

Argher

Limp Gawd
Joined
Jun 23, 2004
Messages
374
Hiya,

I was thinking of possibly powering up to four motherboards off one PSU, as efficiency increases towards a "sweet spot" in a given power supply architecture, as well as noise levels / power cord mess reduction.

Question: I know PCP&C performs custom harnessing... I spoke with them, they said they could possibly get two to three 24pin connectors in a harness, however I also know their PSUs tend to be a bit on the loud side :(.

Are there any other companies that perform similar operations, or would there be other ways (like one picoPSU per board getting powered off a molex from a PSU, hopefully not as expensive as that would be however) of accomplishing this?

I'd love to hear your thoughts :)
 
Argher said:
Hiya,

I was thinking of possibly powering up to four motherboards off one PSU, as efficiency increases towards a "sweet spot" in a given power supply architecture, as well as noise levels / power cord mess reduction.
Click to expand...

Hitting the "sweet spot" with mutliple units doing different tasks may be a bit tricky but if you worked on it you could in theory do it.

Question: I know PCP&C performs custom harnessing... I spoke with them, they said they could possibly get two to three 24pin connectors in a harness, however I also know their PSUs tend to be a bit on the loud side :(.


Are there any other companies that perform similar operations, or would there be other ways (like one picoPSU per board getting powered off a molex from a PSU, hopefully not as expensive as that would be however) of accomplishing this?
Click to expand...

Off the top of my head I can't think of a company that offers such a service to end users. However, the pico idea does work and is done rather frequently with the main drawback being the cost.

Back in the day when systems powered mostly off of the 5v there were a number of people selling 20pin ATX splitters so you could run two motherboards off of one PSU. One of the DC guys here (LPerry aka the weatherman) used to host a page that had a tutorial on how to do it yourself as well and I think links to people selling ready made adapters. I know his EM page has bounced around a bit after changing ISP's so I am not sure if ti is back up.

But splicing 2/24pin adapters from one ATX connector lead (or making a 1 to 2 adapter) and doing the same for an 8 pin EPS connector is indeed possible if you are so inclined. You will need to be careful as you are going to be adding some resistance when you do this. All of the neccesary tools and materials should be readily avaialble from a place like performance pc's. But yeah simply pulling hte pins from the ATX and EPS connector, clipping the wires, and splicing in two sets of leads will get the job done. Now I would not do this for systems that are "critical" or ones that will have a large system draw and of course this all voids your warranty etc.
 
Splicing cables is easy. They make an adapter going the other way, so you should be able to find one pre-made for your needs as well. Or just buy one of these and hack off one of the female leads and replace it with another male. http://www.stayonline.com/detail.aspx?ID=7898

My biggest fear with such a set-up is how the two boards will be affected if you turn one on without the other- it may work for a while, but I would be afraid to do so long-term. The solution is to make sure both systems are on 24/7, but that will run your electric bill up fairly quickly. I'd invest in picoPSU's, honestly- I was planning on doing something similar myself last month, but my expenses got the better of me. :(
 
My main concern with picos is that I'm not sure they'll be capable of driving a dual socket mobo whatsoever. Price is also a concern, but a somewhat lesser one as I would be able to go with a cheaper (relatively) single large PSU, as opposed to multiple smaller.

My concerns with splitters would be possibly too much amperage winding up on the original leads, especially if I was going splitter to splitter (to get enough for 4-5 motherboards), not to mention the resistance incurred by that many connections? I'm fine with them turning on/off at the same time.

The ideal solution would be one I could more or less plug and play in a safe, reliable manner.
 
Argher said:
My main concern with picos is that I'm not sure they'll be capable of driving a dual socket mobo whatsoever. Price is also a concern, but a somewhat lesser one as I would be able to go with a cheaper (relatively) single large PSU, as opposed to multiple smaller.

My concerns with splitters would be possibly too much amperage winding up on the original leads, especially if I was going splitter to splitter (to get enough for 4-5 motherboards), not to mention the resistance incurred by that many connections? I'm fine with them turning on/off at the same time.

The ideal solution would be one I could more or less plug and play in a safe, reliable manner.
Click to expand...
The highest-rated picoPSU is a 120W, which would handle almost anything but a dual-Quad or dual-Opteron. The project I was going to try last month involved a Q6600, and I'm 99% sure it would have worked. I just wish I'd gotten a G0 instead of my B3, for those extra 10W of headroom.
(Reference: Read the hidden text here)

More importantly, I'm pretty sure that 120W rating on the pico is more of a suggestion- it doesn't even TOUCH the 12V line itself, just passes it straight through the source. The only thing the picos do is siphon off some of that 12V supply and turn it into 3.3V and 5V for the PCI slots and RAM.
I'm almost positive that you could plug in a 150W board and it would work fine, although I'd be worried about running so much amperage through the picoPSU cables in that scenario.

As for your splitter+splitter idea to run 4 or 5 boards, I think you're asking a bit much. The resistances are cumulative, and you again need to worry about high amperage.
I'd say your best bet is to eat the cost, get four or five pico120's and solder each one to a separate hard drive lead to avoid risking melted cables.
 
Unfortunately, as you surmised, I am indeed thinking of dual Opterons.

And I entirely agree with the splitters, as I noted, resistance would be crazy, not to mention the power draw on the original cable, plus so many opportunities for a bad connection.

Soldering the picoPSUs might work...but oi, that could be a really, really expensive mistake.

Thanks for your thoughts so far :)
 
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