Hello good morning, when updating the mod to 1.3.1 1.21.1 I had a drop in fps, and well that's all.
(I've noticed that the menu performance is also greatly reduced.)
(I will use a server as an example to show the performance)

The first one shows how the previous version 1.3.0 is for 1.21.1: https://youtu.be/d_cosGXzPoE
(Sorry for the bad quality)

And well here is the new version 1.3.1 for 1.21.1: https://youtu.be/Qb2PQvxMdxU

To get back to the performance I had before, I have to enter F1 mode, as seen in the video.

Now about the LOG, I have no idea which one to send, please if you see this tell me which log I have to send exactly so I can help solve this error more easily.

Well, I hope I have been able to contribute something.
Have a nice day

You can find the log in the logs folder in the .minecraft folder. Upload the latest.log file

Yes, thanks. What CPU and GPU do you have?

Try disabling the fast_buffer_upload option in the ImmediatelyFast config and check if it improves performance again. Its located in .minecraft/config/immediatelyfast.json.

https://hst.sh/eqikixulot.sql this? @RaphiMC

the CPU is AMD A12-9800E-9800 and the GPU is AMD Radeon R7 Graphics, and now I'm going to try that configuration to see if it improves or remains the same.

Hi, I'm back. Yes, disabling "fast_buffer_upload" improves performance.

Can you run this version: https://upload.raphimc.net/file/eAUUchIjwiPxAx83/NmpL2pWgq7Ah3LgX/ImmediatelyFast-Fabric-1.3.2-SNAPSHOT%2B1.21.1.jar and upload the log again. I added code to log all the OpenGL features of the GPU, so I can check why its getting slowed down by the fast buffer upload optimization

I set "fast_buffer_upload" back to true? @RaphiMC

You can leave it false for now

Here you have it: https://hst.sh/necikexuvi.yaml