Destiny 2 SLI Performance Issues

I have been having performance issues with my two GTX 970's in SLI. In public events I get FPS drops down to 55 and the max amount of FPS is usually 75. One of my friends is using one GTX 970 and he averages 135 FPS. Is there anything I need to do to solve these performance issues?

My Specs are :

Ryzen 5: 1600 3.2 GHz 16gb DDR 4 RAM at 3200ghz 2xGTX 970 SLI SSD 240GB