I kinda solved this myself and post here as help for others as it took a fair amount of nerve racking and trial and errors which I want to spare other folks.
After a dozen or so trials and possible ideas of solutions that did not help I stumbled upon a solution to the problem.
Turns out, apparently in nvidia cards, having one monitor connected via display port and another secondary monitor inactive but just plugged into the HDMI socket (HDMI cable length: 5 metres) will cause some power fluctuation problems and some sort of power supply instability to the system when the card is changing resolutions or refresh rates or otherwise under load. Anyways DISCONNECTING the 5 meter HDMI cable and just leaving the one monitor plugged in via display port seemed to have done the trick
))))))
After a dozen or so trials and possible ideas of solutions that did not help I stumbled upon a solution to the problem.
Turns out, apparently in nvidia cards, having one monitor connected via display port and another secondary monitor inactive but just plugged into the HDMI socket (HDMI cable length: 5 metres) will cause some power fluctuation problems and some sort of power supply instability to the system when the card is changing resolutions or refresh rates or otherwise under load. Anyways DISCONNECTING the 5 meter HDMI cable and just leaving the one monitor plugged in via display port seemed to have done the trick
