Rust on mac very laggy

I have recently bought rust on steam for mac and at first the game ran fine after like an hour it started lagging heavily, so i restarted the game and after like 10 minutes it did the same. And now every time i try to play rust i can play for about 10 minutes before it starts lagging again.

I also noticed it was using 200% of my cpu.
Is there a fix for this issue?

Cpu 2 x 3,5 GHz 6-Core Intel Xeon
Gpu Radeon Rx 580
Ram 64
Storage 1 TB SSD & 2 TB HDD

Sounds like an overhating issue