M17x R4, GTX 680m, bad performance

I had got a GTX 680m for my notebook about a month ago after my AMD Radeon HD7970m died. I downloaded newest drivers and put everything on high performance. I tried to play Fortnite which runned at 20fps on medium graphics. So i checked my temp and it was at 59 degrees when i checked task manager it said it was running at 100%. Ive tried a lot of things and i know it isnt Fortnite because i ran minecraft on it and it was stuttering. I dont know if i bought a faulty gpu or if it is a setting that could fixed. Any suggestions on the topic would be great.

Specs:

Processor: Intel Core i7-3610QM

RAM: 32gb

Display drivers: Intel HD graphics 4000 and GTX680m

If you need anything else please ask.