gpu bad performance for low temps

[BardiaMGTGC]

ive been using a asus x556uqk as a portable device for some classes and im having problem with gpu

i had windows and now i have linux mint 19 and im having same problem

it keeps temps down to 65 and does spikes and very bad performance 

it was the same in windows too

i tested unigine valley benchmark and its so bad 

i tested it before on this linux machine like two days ago and gpu temp was getting upto 92c and it was fine

also in windows it was like this for some time and then dropped performance

specs if needed

i7 7500u

gtx940mx

8gb ram

1th hdd

linux mint tessa 19.1