I've had this problem for quite some time now, but recently it happens more often.
This happens every time after I exit out of path of exile, and every 3rd or 4th time I exit a game of league of legends or teamfight tactics. It probably happened on some other occasions, but i didn't notice specifically when. It rarely happens while I'm still in game.
So the issue is that after I exit the game my monitor says "Power saving mode", my fans start running fast and the only thing I can do to get the control back is to restart the PC or force shut it down. I can still talk in discord when the monitor says power saving mode, but I'm not sure if I can control my mouse and keyboard.
I haven't played any games for a while so in the meantime it wasn't happening at all (If it did, it was so rare that I don't even remember).
CPU Intel(R) Core(TM) i5-6402P CPU @ 2.80GHz, 2801 Mhz, 4 Core(s), 4 Logical Processor(s)
Installed Physical Memory (RAM) 8.00 GB
GPU Radeon (TM) RX 470 Graphics