# ATX 12V V2.3, backwards compatible with older standards?



## NoviceTechie (Feb 2, 2009)

Hello,

I recently had issues with my PSU and rather than play guesswork on whether its still functional, I rather just replace it. 

My motherboard is a m3n78-pro. Its a bit dated but I'd like for this pc to last another 6 months before I build an entirely new rig. If I read the manual correctly, it requires ATX 12V V2.0. 

The PSU I'd like to change to (since it just has to last another 6 months) this 900 w PSU. Would the m3n78-pro be compatible with this PSU? One concern I had was that the m3n78-pro requires a 4 pin ATX +12v connector. If I read the PSU's specifications correctly it has one 12V 8-pin (4 + 4) CPU power connector. Is that 8-pin two separate power connector, ie do I just use 1 of the connectors to fit into the 4 pin ATX +12v connector?

Please excuse my noobishness but what exactly does the v2.92 Motherboard specification entail? I tried to google it, but got less useful information and product results from newegg.

Also I read the wiki on the ATX 12V V2.X standard, but it didn't answer my question - is ATX12V v2.3 backwards compatible with the ATX12V v2.0 standard?


Thank you very much for any help you can give.


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## makinu1der2 (Jan 1, 2008)

I wouldn't recommend purchasing the PSU that you linked.

The 12V 8-pin can be separated so that is not an issue.

Get a quality PSU now and you can always transfer it to your new build when ready.

Yes it is backwards compatible.

Power Supply Information and Selection


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## NoviceTechie (Feb 2, 2009)

Thank you for the post. I just read it and am definitely bookmarking it.

The PSU's not ideal, admittedly, but I had a thermaltake toughpower 850w, and its the 2nd time I've had to RMA it. Definitely going to look @ the list of recommended PSU's.

One follow-up question though. What is the V2.92 Motherboard specification? I'm sorry if it was in the post and I skipped it, but does it even matter, or is it a safe assumption that as long as the mobo and the psu employ some variation of the ATX 12V V2.X standard, they should be compatible?


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## sparky195 (Oct 7, 2010)

v2.92 should be the revision number of your particular motherboard

IE: model #1234 v 2.91
model #1234 v 2.92


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## makinu1der2 (Jan 1, 2008)

NoviceTechie said:


> What is the V2.92 Motherboard specification?


See if this helps.


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## NoviceTechie (Feb 2, 2009)

Ah, so if its the revision # of the mobo - is it a safe assumption that a psu stated to be compatible with v2.92 would be backwards compatible with earlier revisions - or is that a set requirement?

Sorry its a noobish question, I just couldn't find the v2.92 # anywhere on the m3n78 pro's documentation.


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## NoviceTechie (Feb 2, 2009)

OH ok, I just read the wiki link. Basically it implies that it is backwards compatible since the specification just requires the 24 pin + 8 pin connector, which may "overhang" depending on how old the mobo is, is that correct?


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## makinu1der2 (Jan 1, 2008)

The v2.92 is not the MB revision number.

It is the latest EPS12V Specification. There is also a pdf document attached to the 

wiki link that I sent you.


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## sparky195 (Oct 7, 2010)

thanks for the correction did not mean to misinform


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## NoviceTechie (Feb 2, 2009)

0,0 ok I think I've read everything now. 

Please correct me if I'm wrong because this is the most reading I've done in a while so i may be putting the info together incorrectly.

EPS12V v2.92 is the latest specification of the EPS12v standard, which MAY or may not be compatible with the ATX12v v2.x standard, depending on the manufacturer. In the example of the PSU I linked in my first post, it is both ATX12v v2.3 compatible AND EPS12V v2.92 compatible.

When choosing a motherboard's PSU, its important that it be ATX12v v2.X standard compatible, not necesarily EPS12V V2.92. The motherboard I linked in my first post was an m3n78-pro and it is an ATX12v v2.0 standard, so its not surprising that I didn't find the EPS12v or the v2.92 specification anywhere on the unit.

Is that an accurate summation?


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## Tyree (May 10, 2009)

Your Mobo uses a 24 pin Power plug. Any new ATX PSU with a 20+4 pin power cable will work. Your main concern is to be certain the PSU is good quality (SeaSonic or Corsair)and has enough power to supply your hardware with clean power.


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## NoviceTechie (Feb 2, 2009)

Sorry for the confusion. Just trying to understand the whole difference between V2.92 and ATX12V V2.x. So the primary concern is the presence of the 24-pin connector and the 8 (4+4) pin connector AND the specification that the PSU I choose is ATX specified, right?



Tyree said:


> enough power to supply your hardware with clean power.


I had an additional question if you don't mind. The topic of "clean power" kept rising when I was reading the literature in regards to multi-rail versus single rail (12v). I was reading this wiki insert and towards the bottom it mentioned that the whole concept of balancing multiple rails was getting cumbersome and it may have been done away with with ATX12V V2.3. Does that mean it no longer needs to be considered when hooking up a motherboard to a psu or is the wiki entry wrong? I mean I don't use that many connections, just 5 fan connections, 1 Sata drive, 1 dvd writer, 1 24-pin mobo, 1 4-pin 12v - so I never really considered the whole balancing issue with the thermaltake toughpower 850w.


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## shotgn (Aug 10, 2008)

The toughpower series is a good psu, It should have no problem balancing out the power.
On the lower quality psu's with multiple rails you get that issue...Should be illegal lol. 

I just prefer to have is simple and purchase a single rail psu. But to each their own


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## Tyree (May 10, 2009)

Single or multiple rails makes no difference if the PSU is a quality unit. SeaSonic, one of the top PSU manufacturers, uses two rails.


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