Been wondering about this

Beerzerker · May 21, 2021

I've mentioned this in other threads before and although I know both, the board and PSU's work fine themselves, when you pair these together they don't play nice at all.

The issue is this:
I have a Maximus VIII Impact that does fine, clocks well and behaves as it should when it's working so no issue with that and I also have a pair of Rosewill Hercules 1600W PSU's that, themselves work as they should and I've been using them for all of my daily use and XOC stuff including WR's I've set along the way. Got one in use with this system right now, the other I set a WR with the other day running a FX-8320 well over 8GHz:
Bones`s SuperPi - 1M score: 9sec 141ms with a FX-8320
So power delivery itself from the other Hercules PSU I'm using is NOT a problem and the one in this machine has been used for XOC before itself and did just as well.

However.....
If I hook up the Impact to either one of these PSU's I do get the standby power light on the board.
Using either the onboard power button or the header pins results in exactly jack, it's almost like I never pressed the power button at all - It just sits there and does nothing.

Then I can either hookup another PSU to the board and it works OR hook another board to either PSU and they work normally.

The problem is specific to this exact board and these PSU's only as you can tell from what I'm describing here.

I can even hook up these PSU's to something really old like a Socket A for example and it works, one of my NF4 939 DFI's (DFI's BTW are picky about everything) or anything else I've got - It just works.
The Impact itself I can hook up to any other PSU I've got except the Hercules PSU's and it fires up and runs normally, OC's well and all else.

It's not like I can't get around the problem because I can, I'm just trying to understand WHY this happens in the first place.
I'm thinking there is something about the PSU's the Impact is seeing when connected and not liking (Protect mode) and that's probrably it but still, it would be nice to know what "It" is.

Thoughts?

Freakwise · May 21, 2021

Hmmm... That is very wierd behaviour, my thoughts was it was somehow those two combination is kinda not synchronized, i read your post again and it was kinda wierd to think ut was the ps_on pin that was vaulty since it was work for other motherboard

And my thoughts was probably it was something to do with "power ok" pin which from what i read basically said

Quote

The power good signal is a +5 volts signal that is generated by a switching power supply when the supply has stabilized its output voltages and passed all its internal self-tests. The is usually generated after s a period of between 0.1 seconds and 0.5 seconds after turning on the power supply.

So i guess the maximus viii is kinda sensitive to the voltage reading and this power supply voltage signal is bit out of spec,

Maybe...

Beerzerker · May 21, 2021

Could be but then again you'd think at least one of the other systems would be seeing this "Out of spec" issue too and behaving in the same way.

I've been thinking it's more board related and could be.