Is -5V really necessary? What is it used for on the MB? What if the motherboard is older (ie not ATXV2.2) but the power supply is a v2.2 ATX specification without -5VDC? Can the MB be used with the newer power supply without -5V?
I'm no expert at the ATX Power specifications, but V2.1 includes -5V, but v 2.2 does not. And then there the ATX12V Version 2.2 that also doesn't include -5V. Why the differences, I don't know, and what are the implications?
I just installed a Zalman ZM460B-APS to my (now aging) Abit NF-7S motherboard and the Abit EQ monitoring software started beeping away with a 'reading' of +3.6V on the -5V rail. Now, I assume this is wrong, on the basis that the Zalman Power supply conforms to the ATX12V version 2.2 spec, which I now know, has 'no connection' on the -5VDC pin.
But not knowing what was causing the problem at the time (I suspected my new power supply was a dud), I reverted to my old supply, but it seems as though the motherboard was otherwise operating ok, without a -5V rail.
Abit's documentation gives no clear guidance on whether -5V is required - but it does show a negative 5VDC pin on the ATX power connector. So presumably it is used for something, but seems to work without!
So, I'm wondering
I'm no expert at the ATX Power specifications, but V2.1 includes -5V, but v 2.2 does not. And then there the ATX12V Version 2.2 that also doesn't include -5V. Why the differences, I don't know, and what are the implications?
I just installed a Zalman ZM460B-APS to my (now aging) Abit NF-7S motherboard and the Abit EQ monitoring software started beeping away with a 'reading' of +3.6V on the -5V rail. Now, I assume this is wrong, on the basis that the Zalman Power supply conforms to the ATX12V version 2.2 spec, which I now know, has 'no connection' on the -5VDC pin.
But not knowing what was causing the problem at the time (I suspected my new power supply was a dud), I reverted to my old supply, but it seems as though the motherboard was otherwise operating ok, without a -5V rail.
Abit's documentation gives no clear guidance on whether -5V is required - but it does show a negative 5VDC pin on the ATX power connector. So presumably it is used for something, but seems to work without!
So, I'm wondering
- what is the -5V used for?
- is the lack of a -5VDC rail on the power supply and issue when used on my ABIT NF-7S motherboard.
- Can I re-install the Zalman power supply with the Abut NF-7S, and disable the Abit EQ alarm for -5V without problems?
What he's saying is that you have no need for it with the newer power supply and should have nothing to worry about it. I couldn't imagine any problems arising from it.