Performance Issue

Hi.

I'm experiencing more and more performance problems with my spec, particulary when the amount of mobs is increasing when I'm running a maps with blight, delirium, abyss etc...

My spec are

OS : Windows 10
CPU : I7-4790K
RAM : 32 Gb
GPU : GeForce GTX 1080

I know it's an old configuration, but I never had this problem before

Blight is the most problematic encounter, my FPS can fall to 1 or 2 ms

My graphics drivers are up to date and I tried by uninstall and reinstall the game once but I still get this issue.

Can you help me ?