Locked on lower resolution with RTX 2080 Ti, BenQ monitor

[kygregkim]

Hi,

I wish I had a second rig to test this but unfortunately, I don't so I am posting the question here.

I have an old PC, ASUS B85M-G Mobo with i7-4770 with monitor BenQ XL2720T (120Hz). Recently I bought Asus Rog Strix advance RTX2080 Ti and Corsair HX850i PSU. Connected to monitor through DisplayPort.

The problem I am having is on boot up, the resolution will stay locked to something around 1280 x 768 60Hz and the computer does not give me any higher options but lower(checked on Nvidia control panel). Restart won't fix it and the only solution is to unplug the DisplayPort and Plug it back in! and it is back to 1920 x 1080 with 120Hz. It baffles me that simply replugging the DisplayPort fixes it all the time.

I am on Windows 10 version 1803 (OS build 17134.472).
I tried both 417.35 and 411.70 Nvidia drivers with the same result.
The B85M-G BIOS is updated to most recent version 3602.

Any idea on where the fault may be? DP cable? The Card? driver? windows version? monitor? motherboard? I will be buying new CPU and MB sometime early next year so if it is Motherboard compatibility issue, I can rest easy but I have no clue! Thanks for your time.

 

[ebosss03]

The cpu and mobo will have nothing to do with this. If i would have this problem i would start with benching the GPU if it actually can get the expected performance it is not the GPU however if it does a poor job then the GPU is not working properly. Second i would replace the cable to DP 1.2 or higher. The third option would be to try an HDMI 1.4 or higher.

 

[kygregkim]

The cpu and mobo will have nothing to do with this. If i would have this problem i would start with benching the GPU if it actually can get the expected performance it is not the GPU however if it does a poor job then the GPU is not working properly. Second i would replace the cable to DP 1.2 or higher. The third option would be to try an HDMI 1.4 or higher.

Thanks for the reply. When replugging the DisplayPort cable, I get full 120Hz(it says 119Hz) and performs fine, GPU temps are always low and no issues to note on. (FurMark gets a reasonably similar result with others with similar spec, also I ran it for 20~30 min with no problem and performance constant all the way through)

The DisplayPort cable that I am using is 1.4 Although I haven't tried 1.4 or higher HDMI, my monitor does not support 120Hz through HDMI because it is an old model.

To add on to the symptoms, when the screen goes to sleep and I wake it, I get the same issue of fixed resolution reduction and it is also resolved by replugging the DP cable.

replugging DP cable every time I boot my computer is no hassle but I don't see it being a very sustainable option for long term.