My configuration is the following: Windows 11, internal display connected to iGPU and external UHD display to nvidia-HDMI port, multiple firefox windows are opened (1 one the internal screen, 2 on the external). Then in Windows->Settings->GPU I can select firefox to run on either iGPU (powersaving) or on Nvidia GPU (max perf), the problem is the following: Whenever I set firefox running on iGPU, there would be a massive stuttering/framedrop on an external display (connected to NVIDIA), while a perfectly smooth browsing on internal display, and vice versa. My first attempt was to disable webrenderer compositor or switching it to a software rendering, which fixes the heavy stuttering, but the scrolling becomes overall less fluid/responsive. However, setting "layers.gpu-process.enabled" to "false" seemingly solves this problem completely. Now I have a perfectly smooth scrolling on both displays, regardless of which GPU is used in Windows->Settings->GPU (nvidia's is arguably a little but more responsive). Hope this helps someone, or maybe dev team could look deeper into this. Thank you for the great browser!