Opened 7 days ago
Last modified 6 days ago
#24585 needinfo defect
JOSM is running with low FPS on 4K screens.
| Reported by: | anonymous | Owned by: | anonymous |
|---|---|---|---|
| Priority: | normal | Milestone: | |
| Component: | Core bugreport | Version: | latest |
| Keywords: | Cc: |
Description
I’m running JOSM on my Mac Studio M3 Ultra, 96GB RAM, tons of CPU cores, latest JOSM from homebrew, latest MacOS on a 4K 240hz screen.
But JOSM is just running slow, making it barely usable for me. I had the same experience before on Windows 10 with 48GB RAM on a Ryzen 2600, same 4k 240hz screen.
Here are some example videos
https://youtu.be/FpDl-ma0AOs
https://youtu.be/vvaKYz047O0
Related discussion: https://community.openstreetmap.org/t/josm-very-low-fps-on-4k-screens/140048
I see that JOSM is using a merely 3gb of RAM.
Based on the behavior that higher resolutions get slower, I assume that some calculation is exponential and I run into single core performance limitations.
Just moving around the end of a new line makes the CPU load go to 100%+.
When I remove all downloaded data, the new line still consumes 100%+ CPU, but at least it's nearly smooth. I'm only downloading a small Zurich area, nothing insane, 150x150m.
If you think this is RAM related: For Java tools you need to specify the available RAM when starting. Please adapt the start script with a higher value of available RAM. Does this help?