After many hours of frustrating crashing and tweaking with various settings I have found a solution for my power crashes caused by my GFX card (RX 480) I will state my solution below:
1) Open up Radeon Control Centre
2) Click the Gaming Tab
3) Select the problematic game.
4) Make sure all graphics options are disabled
5) Click 'Tune Game Performance' button
6) Select Tuning Control - Manual
7) Make sure Zero RPM option is disable if displayed.
8) Select Fan Tuning - Enabled & Advanced Control Enabled and increase the RPM graph a little
(Specially the 42-85 degrees)
9) Select Power Tuning - Enabled and move the power limit (%) too -10%.