Question Computer Freezes When I Turn on a Turned off Monitor

Feb 26, 2020
I am new to the forum, so let me say hi to everyone!

I have a problem with my PC. I am not sure if "Systems" is the right category to post this, as I’m not sure the issue has to do with the system (it may be a hardware issue or a matter of "wrong settings").

My PC is extremely powerful, I bought it about a year ago. It was very expensive, I chose the components with the help of a friend of mine – a developer (IT guy). I assembled it myself. Until recently, everything worked just fine. The freezing occurs when I turn off the monitor and then turn it on again. Until I turn it off, everything works with no issues. After I turn it off, the PC is still responding to user input (for example, if I press the "num lock" button on my keyboard, the corresponding light switches off, etc.), but as soon as I turn the monitor back on (even if I do so a few seconds after turning it off), the PC freezes (I can tell it has frozen by looking at the PC’s status in TeamViewer, which I use to remotely access my PC and use it for work – it shows up as offline in TeamViewer; or if I press the "num lock" button, the corresponding light does not respond to that – it doesn’t switch off anymore), and the monitor shows the error message "No signal detected".

I have no choice then but to reset my PC using the "Restart" button on the PC case. Event Viewer shows a record of the PC being turned off the hard way, it says something along the lines of "The system was not shut down properly", but it doesn’t give me any specific information that would point to the root cause. Therefore, it is extremely difficult for me to diagnose where the problem lies.

I bought the monitor together with the PC. It is a 31.5-inch one (BenQ EX3203R), it is connected through a DisplayPort cable directly to the graphics card. The graphics card is an RTX 2080 (MSI GeForce RTX 2080 SUPER GAMING X TRIO to be precise).

I use Windows 10, version 1909, build 18363.657. It is a legal Windows copy.

What is also worth mentioning is that this freezing does not occur immediately after I turn the PC on. For example, if I turn the PC on and the OS loads, I can turn the monitor off and on again as many times as I want and the computer doesn’t freeze (provided I do this immediately after the OS initially loads). The freezing always starts to occur only after I’ve actively used the PC for some time.

Furthermore, if I put the computer to sleep or hibernate it (or, logically, if I turn it off altogether), I can safely turn the monitor off and on again and then turn on the PC and everything works without problems. That is, if I turn the monitor off and on while the computer is asleep (or hibernated, or completely turned off). Should I turn the monitor on after turning on the PC first, the PC would freeze.

Said friend of mine told me this could have to do with 2D–3D switching (or something like that), but I did not understand much of what he was saying. I am no computer expert. He also advised me to use another graphics card connector or monitor connector with the DisplayPort cable. I tried that, but the result was the same (the freezing did not go away).

I hope I’ve explained everything thoroughly. A big thank you to all of you who decide to help with this one.
Feb 26, 2020
full system spec? include make and model of the psu
Sure, thank you for getting back to me so quickly.
Motherboard: MSI MPG Z390 GAMING PRO CARBON AC - Intel Z390
Processor: Intel Core i7-9700K
PSU: EVGA SuperNOVA 750 G2
RAM: G.SKILL 16GB KIT DDR4 3200MHz CL16 Trident Z RGB
Graphics card: MSI GeForce RTX 2080 GAMING X TRIO 8G, 8GB GDDR6
SSD (on which the OS resides): Samsung SSD 970 EVO PLUS, M.2 - 1TB
HDD (used alongside the SSD): Seagate BarraCuda 2TB
CPU cooler: Fractal Design Celsius S36
Computer case: Evolveo Ray 5RB
Added fan (in the back of the case): Be quiet! Pure Wings 2 140mm
DisplayPort cable: DP 1.2