Question GPU causing HDMI signal loss with fans speeding up?

Nov 15, 2021
So I currently have a Asus Predator G3-710 prebuilt PC that I was given to by my cousin after he built his own PC. I've had it since Spring of 2018 and previously my cousin had it since early 2016. So its over 5 years old now and it still works pretty well for the most part.
The only thing I've had to replace was the CPU fan and heatsink as the old fan died and was causing my CPU to heat up pretty bad. New fan w/ new thermal paste and its dropped from 95c to 60c so that's good.
However now I'm starting to notice another issue and I'm not sure if its GPU related or RAM related. When I play some memory intensive games (In this case it seems to be happening on Paradox's Imperator Rome) My RAM usage goes up to 90% and GPU temps. reach around 75c-80c. Seems fine and no big issues occur but after a few mins of gameplay, my monitor loses its HDMI signal and I can hear what I believe is my GPU fan go full blast. Game is still running as sound can still be heard and I can even alt-F4 to shut the game down however, I cant unplug the HDMI or anything to fix it and I have to Hardpress my PC off and then on in order of it to work again.
Been looking around at similar situations from other people and I've gotten everything from faulty RAM stick, PSU going bad, GPU problems, bad HDMI cords, monitor problem, etc. I can rule out cord and monitor as I've switched them out and still happens.
Any advice as to what I can pinpoint the problem to and if so, which part I should get to replace it with that is reliable and nor overly expensive. Thank you in advance.

CPU: Intel Core i7 6700
Motherboard: Acer Predator G3-710
RAM: SK Hynix 8GB x2
PSU: Liteon ps-7501-5 500w