Are these PSU readings ok? Also weird RGB light behavior when switched off at the wall

GregI · 25 Jan 2022 at 13:09

I have a 5950x on a Dark Hero motherboard. I currently only have a 3070 but bought a Corsair RM1000x (2015 model) as it would allow easy upgrades to whatever Nvidia comes out with.

I know software readings are far from accurate but I believe they should give a decent understanding of any potential issues. While pure idle in the BIOS or Windows (hwinfo64) my 12v rail is showing 11.984v

However, any slight change in load such as moving the mouse or a program requesting data (I guess anyway) puts it to 11.928v.

During a game it shows it can dip to 11.872v. What I don't understand is this is when the 3070 was drawing over 200w and the CPU about 70w. During an all core cinebench run the rail goes to 11.816v
I know stock the 5950x can draw about 135w so how on earth is the 12v rail lower than when a 3070 is sipping more power?

Another weird behavior that initially led me to check this stuff. When the PC is shut down the keyboard rgb, the white start button led on the motherboard and the i/o cover rog rgb is still active.

The problem is this also happens when the switch at the wall socket is turned off... it only goes off if I switch the plug off at the back of the PSU. From then it doesn't matter if I have it on at the wall socket or not, no lights will shine. How on earth is the board getting power from a socket that's not on?

GregI · 25 Jan 2022 at 14:13

@VersionMonkey @SonicSW20 I thought it would be something like that so I went to sleep. Woke up and the lights were still on. Either 8 hours isn't enough to discharge the caps or it's getting power while off at the wall. What I'll do next time is pull the plug and see if the lights stay on.

@HecFam Yeah I found the BIOS option to do it (Stealth mode) but again this is just masking the problem rather than fully fixing it.

GregI · 25 Jan 2022 at 15:13

Okay my god... I figured it out. When switching off at the wall I noticed it didn't make the "click" noise more of a mushy feel. What was happening was even when the switch was visibly off I had to really press down at the bottom part to hear the click. This is explains why the lights stayed on all night... it actually was on lmao. All behaves fine now (lights go off after about 5 seconds) when actually switched off at the wall.

Only reason I figured it out was because I changed sockets and my surge protector light was still on after I switched it off.

So yeah only issue now is seeing if these 12v rail voltages are fine.

GregI · 25 Jan 2022 at 18:03

@Mr Evil Makes sense.

I honestly think I'm just trying to find issues with the PC at this point and it's not healthy. You spend months planning this stuff and reading about people who have horror stories with their PC that when something just works for you, it's hard to take it at face value.

That's the aida64 stress test passed. Max 70c temps on this 16 core.

I stumbled upon a forum post by the hwinfo64 author in relation to another high end Asus board: https://www.hwinfo.com/forum/threads/voltage-rail-readings.5684/

0.096v accuracy is indeed interesting. If I take my normal 11.928 reading and add 0.096 I coincidentally get 12.024v which kind of makes sense and would match most reviews (tpu review has 12.030v).

If I add that value to the worst case value under aida64 stress test/cinebench of 11.816 that gives me 11.912v

GregI · 25 Jan 2022 at 22:11

Damn that's some great testing, couldn't ask for better especially in my scenario.

I'm a noob when it comes to power stuff but safe to say the motherboard sensor is always lower than what is actually being fed? 12.301 to 12.152 seems like a pretty stark difference but you know I hope it's accurate. If I put a similar load on my 5950x it goes to 11.812v sometimes. If I added the difference you experienced then the rail would actually be 11.961v which would be more than reasonable.

GregI · 26 Jan 2022 at 22:36

@Mr Evil Two things.

1: Your sig link still takes you to .eu so it doesn't work till you manually change to .com
2: My brother has an RM850x that I know is good. He's had it for about a year and never had a problem so I persuaded him to give it to me. My own science experiment.

I never did extensive testing like before but I'm basically getting the exact same voltage numbers I'm accustomed to seeing in hwinfo64 with the RM1000x. The only slight improvement was the 5v rail. Instead of 4.960v it actually showed 5v sometimes but mostly the standard 4.960v. The motherboard sensors definitely are likely being heavily quantised as you said before. It's almost inconceivable I'd get 2 different power supplies that literally give me the exact same sensor values. I bet it's just something like "if you detect a voltage around 12.0xx display 11.928". If voltage drops by this certain percentage then display "11.928". Repeat for 11.872 etc.

Anyway I think I'm happy now. Learned a decent amount about power supplies (well what to look out for anyway).

Edit: Now I think about it I've literally never seen a value on the 5v rail besides 4.960v and 5.000v. Again good evidence of heavy quantisation happening?