After the 1.4 update a saw a massive increase on the overhauled maps which I found strange since they were looking more 'taxing' than before such as Gaza. There a get a stable 50+ with 100 players on it, but on Bamyan it can drop all the way down to 14. I'm not sure what the hell is causing this problem and I find it very strange since I play taxing games like Witcher 3, BF4, Project CARS, Arma 3 etc... fine.
Here are my specs:
CPU: AMD FX 6300
GPU: MSI GTX 1060 Gaming X
MOBO: MSI 970 Gaming
RAM: 8GB Crucial Ballistix
HDD: 1TB (no ssd)
Ty in advance

EDIT: Just done a solo fly over Al Basrah with heli and fps drops to 38. CPU usage peaks at 55% on Core 1 and 10% on others. 30% GPU usage