[SOLVED] My pc started just by pressing the psu switch

[SilverPigtail]

Hi all,

Yesterday I turned off my computer and then I pressed the psu's switch off. Today, I pressed the psu's switch on, and without pressing the case button, the computer turned on itself by a few seconds and then it turned off. After that I can turn on the computer without a problem, but I'm a bit worried. Is this normal?

Specs:

PSU: Bitfenix 850w plus gold
CPU: i7-9700k 3.6Ghz
GPU: RTX 2070 Super
RAM: 16GB DDR4 HyperX

 

[jonnyguru]

Why are you turning off/on your PSU with the switch on the back?

 

[BogdanH]

Is this normal?

No, is not normal. Or I better say, it's not what I would expect how PSU behaves after power cut: after power (from the wall) comes back, or after you turn PSU switch to ON, PC should go directly to standby mode. I don't say there's something wrong with your PSU.. it just behaves unusual.
Anyway, you should also check BIOS, if there's some setting related to "after power comes back".

 

[Jacozeelie]

My pc does that when i do a bios reset

 

[jonnyguru]

My pc does that when i do a bios reset

Right. XMP settings are stored in RAM, which is powered by +5VSB. If you cut the power to your PSU, you lose those settings. If the BIOS is set to "auto" for memory settings, it will try to reconfigure the RAM on the next power up, but this takes some time.

 

[BogdanH]

XMP settings are stored in RAM, which is powered by +5VSB. If you cut the power to your PSU, you lose those settings....

That's not true.
XMP profile is stored in BIOS EEPROM and it's data isn't lost on power cut.

 

[jonnyguru]

That's not true.
XMP profile is stored in BIOS EEPROM and it's data isn't lost on power cut.

IF you set it in the BIOS. If it's set to auto, it's not. And it's surprising how many people never go into the BIOS and set their RAM speed. Just read any review for memory on Amazon, Newegg, etc.

So, the BIOS is kept by the battery, so those settings are kept if they're made in the BIOS. But +5VSB powers the RAM in standby and if you kill the +5VSB, the board sees it the same as you taking the RAM out of the PC and putting another set back in.

 

[jonnyguru]

No, is not normal. Or I better say, it's not what I would expect how PSU behaves after power cut: after power (from the wall) comes back, or after you turn PSU switch to ON, PC should go directly to standby mode. I don't say there's something wrong with your PSU.. it just behaves unusual.
Anyway, you should also check BIOS, if there's some setting related to "after power comes back".

He said it turned on and then turned off. If "state after power failure" is set to "on", then the PC would actually turn on and POST.

 

[SilverPigtail]

Ok, sorry for the wait.

First of all, I turned off the switch that day because I thought I would be a few days out of my home. Secondly, maybe it's because the residual supply because I didn't press the turn on button when I switched it off?