Performance issues

I'm enjoying this league but the stuttering is getting out of hand. I've tried editing audio and config files. I've tried a bunch of different things recommended in various posts but the performance just gets worse and worse as the mobs get denser. I just got power charge explosions on my bonestorm and it just cooks it.

Or maybe because it's night time on the weekend and the servers are overloaded, I really cant tell.

My PC is not high end but it's not a piece of shit either. Do I really need to invest in an expensive rig? Would this even help or are there performance issues even for people with good PCs?