Why is DisplayPort not working correctly on my configuration?

Question

Video cards

Hello. I recently bought a new Acer Nitro XV240YPbmiiprx monitor, problems arose after connecting via the DisplayPort cable that came with the monitor. If anything, in cable 20, the contact is not connected, that is, there can be no problems with this. The bottom line is this: firstly, I can’t enter the BIOS, POST is not displayed, the motherboard logo is not displayed when the system starts. If I just press DEL to enter the BIOS, I can do it, but the monitor will still not display anything, no matter how long I wait. The picture starts to appear only when Windows is almost loaded. After loading, there are other problems: when the display turns off after a certain time, the monitor goes into standby mode, if I try to wake it up with the keyboard or mouse, the blue light comes on (as if a signal is appearing), After a while, he writes that there is no signal and again goes into standby mode. The only thing that helps is turning the monitor off and on with the button. Also, I can’t turn on 165 Hz in the NVIDIA control panel (if I click apply, the monitor simply turns off for ~ 20 seconds, then turns on at 144 Hz, but 165 is no longer possible to turn on (this item disappears in the drop-down menu)). I installed DP version 1.2, 1.4 in the monitor, turned off DDC / CI, turned off automatic source detection, manually setting DP, nothing helps. I also put it from the office. NVIDIA site but 165 enable already the possibility does not appear (in the drop-down menu this item disappears)). I installed DP version 1.2, 1.4 in the monitor, turned off DDC / CI, turned off automatic source detection, manually setting DP, nothing helps. I also put it from the office. NVIDIA site but 165 enable already the possibility does not appear (in the drop-down menu this item disappears)). I installed DP version 1.2, 1.4 in the monitor, turned off DDC / CI, turned off automatic source detection, manually setting DP, nothing helps. I also put it from the office. NVIDIA sitefix for DP , but did not help. How to be? Now the monitor is connected via HDMI, 165 Hz is available (and it works properly!), It wakes up after going into standby mode, I can enter the BIOS without any problems at all. But I need to deal with this problem, because I either go to hand over this monitor until 14 days have passed from the date of purchase, or make sure that the problem is in my configuration. Could this be related to the old motherboard or my OS?
Configuration:
Motherboard: Gigabyte GA-EX58-UD3R (rev. 1.6)
Video card: MSI GeForce GTX 980 GAMING 4G;
Processor - Intel Xeon X5670;
Power supply - Cooler Master SilentPro M850;
OS: Windows 7 SP1 x64.
The rest does not make sense to specify, as it seems to me.