Looking for PSU: High Efficiency at Low Power with EPS12V

fwki · Post by **fwki** » Fri Mar 07, 2008 7:22 am

I am running a low powered server with a Tyan S3095 MB that "requires" an EPS12V spec PSU with the 8-pin power connector. The problem is that EPS12V PSU's are high powered and the 80+ ratings are only applicable at loads far above the 30w idle 50w load requirements of my server. At this low draw the efficiency is around 60-65%. I know the potential reduction is only like 10W, but that's another HDD. I have a request into Tyan support about using an ATX12 4-pin cpu power connector into the 8-pin MB connector, but I have a feeling I'll get the company line about how requirements are requirements.

Does anyone know of a low power, high efficiency PSU (ATX form factor) with EPS12V specs? I have a Seasonic Energy+ 550 in there now.

lm · Post by lm » Fri Mar 07, 2008 9:04 am

You won't probably ever come even for the wasted power of building a new PSU with the saved electricity of a bit better efficiency for that low loads.

fwki · Post by **fwki** » Fri Mar 07, 2008 9:45 am

I have a new home for the Seasonic 550, so I am buying a new PSU in any case. It would be nice to save 10 watts if only for bragging rights.

Post by **MikeC** » Fri Mar 07, 2008 9:54 am

Personally I wouldn't sweat the 8-pin plug. Chances are, the 12V pins on that plug (on the mobo) are in parallel. Just check the trace on the PCB. A 4-pin will work fine; the specs are for extreme power demands and your CPU obviously doesn't have them.

Test the board with just the memory on a standard ATX w/ 4-pin AUX12V. I don't very much you're going to hurt anything. After making sure it work,s go ahead and get the most efficient low power PSU you can find. A picoPSU might be an option.

fwki · Post by **fwki** » Fri Mar 07, 2008 7:47 pm

Mike that seems to be a consistent message in other forums too so I'm going to test with a Fortron ZEN FSP300 from an aborted HTPC build. I think this server could run with a pico but not much headroom for additional HDDs. If that works then the 550 goes to the gamer replacing an Earthwatts 380 that is not exactly silent.

fwki · Post by **fwki** » Sat Mar 29, 2008 11:23 am

As a follow-up to using 4-pin power connector on the Tyan S3095, I have had full stability using the FSP ZEN 300 fanless psu. Tyan online tech support's response to the issue was as follows:

"We do not recommend it. It usually works though. If it posts it will be as stable as an 8-pin, if it doesnt post you will know why. Plug the 4pin into the 8pin."

Mike, you were on target: no problema.....