[HELP] RX 570 Power Problem

[UnoSee]

my gpu starting to behave strangely on certain games like watch dogs 2, Assassin's Creed Syndicate.

games that not affected : GTA V, Pc building Simulator, Hacknet

The game started to lag at the main menu then works fine for 1-2 minutes then drop from 80-100 fps to 15-30 and the power drop from 130 watt to 50-60 the problem started there

 

if you want to see it on action i have video footage of it happening