What to do with extra rail?

[davidm71]

I have an old PC Power and Cooling 850SSI that I never really used because I later found out its wattage is split up into three rails and wasn't recommended for the SLI rig I wanted to build. Anyhow, I'm going to be building a new system and I still want to use this psu but I was wondering if anyone knows if its possible or even a good idea to utilize the extra 12v rail that was intended for a second cpu to power a video card or something else?

Thanks.


PS: The rails are split like this: the main 12v rail has 30amps, then the other two 4-pin plugs for the cpu split the remaining 24 amps. Not sure about the 3.3 and 5 volt rails.

 

[JonGerow]

Are you sure about the connector and rail distribution on that?

I mean, I know PC Power initially goofed up how they distibuted connectors on split +12 rails, and that's why they started the heavy "single +12V rail is best" campaign (as if everyone else goofed up just as bad), but dedicating 24A to just CPU is just nuts.

 

[JonGerow]

I can't find the 850 SSI on PC Power's website, but where I am seeing it it is listed as having four +12V rails rated at 17A each. So that means that w/o the CPU you would have up to 34A available.

 

[Arcygenical]

Use it to power the various 12v devices about your room, like I'm doing

 

[davidm71]

Not sure how those rails are split up exactly, but it would be cool if you get an 8-pin adapter hooked up such that you could power a 9800gtx or something...

Here is a view of the specs from the label:

Though mine is a little different with only three 12V rails at 16,16, + 30 amps. This one has 17, 17, 17, + 17 amp separate rails....

 

[JonGerow]

Not sure how those rails are split up exactly

Then why did you assume that all of the power went to the CPU?

Here is a view of the specs from the label:

Umm.. that label shows FOUR +12V rails at 17A each. So even if the CPU is across two rails with the 8-pin, that's still 34A available to everything else. Not 30A. You said yours had THREE +12V rails. Which is it?

 

[davidm71]

I edited my last post to correct that fact. Apparently PC Power has two different versions of the 850 SSI. Mine has 16, 16, + 30 amp rails. I'll try to post an accurate label.

Thanks.

 

[davidm71]

A year and a half ago when set out to build my SLI Rig I purchased the parts not all at once. I wasn't sure that the 850 SSI could handle a dual 8800GTX setup and I called PC Power and Cooling and they advised me to stick with one video card and one hard drive because they said the rails were split up. Long story short, got into a big arguement with them about false advertising and they agreed to drop the price on a 1kw single rail model by a $100 to $400 which I purchased. So this 850 SSI has been idling in my closet ready to go and I want definitely maximize the potential this psu has even if I have to run my cpu cooler fan off of the extra 12v Rail!

Dave.

 

[[Spectre]]

Yeah there were two versions. However, most of the information on those units has been dissapeared except madshrimps review of the 4x12v and the labels that were posted at JG.com

 

[davidm71]

http://www.maximumpc.com/forums/viewtopic.php?t=75714&sid=76263ee05b1c928f69d5d1bcec674040

 

[JonGerow]

Yeah... this is the kind of thing that PC Power did in the past that made them switch to single +12V rail. Unfortunately, they used a bit of FUD to cover their tracks and now make blanket statements about how multiple +12V rails cause "trapped power". *sigh*

That said... I would think that you could have PC Power "service" the unit to make it a single +12V rail, or at the very least re-arrange the wiring so the 4/8-pin is on one rail (16A), four PCIe connectors on another rail (30A) and everything else on a third (16A). This woud be an ideal arrangement for that PSU. Yeah.. they'll charge you for doing it, but it gives the PSU some value. Right now, you could only run one GTX or Ultra or a pair of lower end graphics cards (like a pair of G92's).