PhysX Particle Decay and Multithreading in Borderlands 2 UE3

Hey guys, I’ve spent a long time searching the internet for solutions to no avail. This seems to be a pretty widespread problem in the community and I was hoping you might be able to help.

The problem is, on modern hardware, PhysX set to high tanks performance in large battles. We’re talking people with modern i7s and 1080s get sub 20 FPS. Originally, a 680 was enough to run it buttery smooth. Something has changed. The problem seems to affect 900 and 1000 series cards the most but there are rumors that somehow PhysX multithreading was broken in one of the last DLC updates. In any case, the problem is definitely CPU bound.

The community for the game is still very large. Steam reports 2000+ people playing at any given time. Lots of people have tried finding solutions but haven’t found anything ideal. The best we’ve come up with is editing MaxParticleResize in the UE3 config files to limit the amount of particles at any given time. The big problem with this is that as soon as the particle limit is reached, no more effects are produced.

I’m guessing fixing the application’s multithreading can only be done by the developers, but correct me if I’m wrong. What I’m hoping for, barring that, is some way to aggressively cull particles to allow new ones to be created. As it is, the game will produce either infinite particles (thousands upon thousands on screen at once) or will just stop at a certain point once a set limit is reached. Perhaps something can be changed or added to the config files that we haven’t figured out or perhaps some hex editing might be in order? I’m definitely open to any suggestions! It would be a dream if Nvidia actually stepped in and somehow fixed this with a driver update!

Anyway, thanks a lot for your time. I hope to hear from you guys.