Question What is wrong with my system?? I'm stumped...

[iShipwreck]

Built my computer about 5 years ago. Never had any issues, daily use. A while back is just started shutting off randomly. I would have to turn off PSU and leave it for a few minutes before I can return to turn the computer on. Does well for a while (maybe a day or two) before it starts acting up again and shuts off. Now video is super choppy and computer performance is a bit laggy all the time. Gets worse the longer it's on. System is well taken care of, no dirt or dust buildup, cleaned regularly. I ran diagnostics on RAM, drivers, etc. No errors. No drivers needed updating. Unplugged and removed GPU. Still same problems. Ran /CHKDSK, and sfc /scannow, no issues. Monitored temps through Open Hardware, all seems normal. Did fresh re-install of windows (system restore). Same problems, nothing changed. In Task Manager there doesn't seem to be anything out the ordinary hogging my system..

I'm just lost now. I don't know what else to check or what it could be.. Everything comes back normal but my computer still behaving weird.

CPU: i7-4790k
MOBO: Asus Z97-Pro
GPU: Asus 750ti
PSU: Corsair CX 750 (I know it's way more than I need I built this a long time ago not knowing all that much and planned on upgrading system in the future)
SSD: Samsung 840 Evo (120GB)
HDD: Seagate 1 TB
Custom water cooling loop

 

[Deleted member 14196]

Psu problems maybe. Start troubleshooting use memtest86 to test your memory use hard drive testing software to test the hard drives and possibly test with a different power supply to see if that was the issue

 

[Barty1884]

How is airflow in the case? Are you overclocked?

Potentially could be the VRMs heating up, if there's minimal airflow and you're overclocked. A custom loop removes 'normal' airflow over components & tends to be limited to exhausting via a rad.

With decent airflow in the case &/or stock operations, that seems unlikely.

Did fresh re-install of windows (system restore).

As an aside, a system restore... restores the good/bad/ugly and is not a "re-install" of Windows.

 

[iShipwreck]

I thought it could be PSU but that wouldn't cause lagging sytem and video?

No overclock, airflow is good, I have 6 chassis fans. It cleared my system and re-installed windows. I had to backup personal files to my Google Drive.

 

[onespeedbiker]

I thought it could be PSU but that wouldn't cause lagging sytem and video?

A bad PSU can underpower/ under volt a GPU/CPU causing a lagging system and video.

 

[iShipwreck]

A bad PSU can underpower/ under volt a GPU/CPU causing a lagging system and video.

Ah. Makes sense I suppose. I thought it was either on or off, no inbetween. I'll do the memtest86 and then (if it check out okay) bite the bullet and get a new PSU since I don't have one on hand. Good thing they're cheap.. Thanks.

 

[iShipwreck]

Bought a new PSU and installed it. Same problem persists. I also removed all but one stick of RAM and did memory diagnostics on each one (exchanging one stick out for another once check was finished), no issues. Software and malware checks find nothing wrong, computer finds nothing wrong with hardware, not a PSU issue, not overheating, no overclock... I have no idea what's going on but performance sucks and still shuts off without notice, not even a BSOD..