I had a 1060GTX 6g EVGA Mini , I could barely do teamfight, as soon I had around 20-30 player fighting, my FPS was going around 15-25FPS ( This is before Performance Patch tho).
I have a old CPU 4790 i7
I switch for a EVGA 1660Ti and its like Day and night. I have 144FPS and probably around...