N E W S F L A S H
GPU Fans haven't been spinning - Likely since i installed the M.2.
Fixed it, cabling came loose from a plug [As in the individual cables that lead into the plastic casing].
re-inserted the cable into the plug, plugged it back in.
Haven't had issue since.
Basically the worst coincidence i could have had, and looked in the wrong direction for a week. Also learnt that if my GPU fans dont spin up, the GPU will clock low enough to stay under 75c. So i didn't immediately realise there was an issue.
But yeah, fixed the cable, Fan's getting power, may have bumped the cable when installing the m.2? dunno.