Did u use li-on charger ? if so smart charger will ignore to spike for terminal with voltage < storage voltage!! am asking to try with raw 5V DC from power supply( with right +ve & -ve match)
(If you dont have experience in DIY, please dont do.)
You can try this, but if its resolves temporarily, then go with RMA. I too faced issue with galahad & as he said, the 1st version have issues with internals.
What is the temperature you got running w/o overclock with cinebench? The default PB seems good to drive most games, do you see any game performance issue with default setting?
Also this galahad is not good enough to drive this beast at Indian condition as far as your ambient temperature is low.
If you are using Samsung SSD, try installing its driver and check once. Any USB device apart from KB/Mouse? if so remove and check. Also default you bios to check. Update your chipset driver once.
Its weird, have you installed the nvidia driver ?Can you configure the refresh rate in nvidia control panel ?
do clean your nvidia driver with ddu & re-install once and check