4.19 particle mesh emitters cause heavy FPS drops


After updating my project from 4.18 to 4.19, I started getting huge FPS drops in regular intervals. I managed to trace back the issue to particle systems with mesh emitters and could reproduce the problem in an empty new project with a default particle mesh emitter (download link below). The FPS drops start out small, but get progressively worse the longer the editor is open. After a minute or two, “stat unitgraph” looks like this:

Download sample project (509 KB):

I couldn’t find any information about this behavior, so I have no idea if this is “by design” due to some new feature in 4.19 or if it’s a bug. Does anyone have any idea what’s going on there and how I can prevent or work around it? Should I simply report it as a bug and hope for a hotfix?

Any help would be appreciated.

I tested the project linked above on a different machine today and didn’t run into any issues, so I assume it’s a hardware-specific bug. I’m working with a GeForce GTX970 (latest driver), the PC without the issue has a Radeon R9 200 Series. It would be great if someone could test the project and report whether or not it’s running smoothly.

As a point of reference, here’s a video of how it looks on my PC (you’ll have to skip through the video a bit to see the render time spikes increasing over time):

Another quick update: The problem also occurs with a GTX 1080, so I assume most or all Nvidia cards are affected. Although that’s hard to believe when apparently no one else seems to care about this issue.

Your issue is most likely somehow related to the issue discussed in that thread.

Thanks! It does indeed appear to be the same issue. It’s good to know I’m not alone with this.