CURRENT: bad performance in LibreWolf, Firefox, mplayer

Hello,

running CURRENT (FreeBSD 15.0-PRERELEASE #3 master-n279925-393356f25fb8: Thu Aug 28 06:53:41
CEST 2025 amd64) on a moderat modern hardware (AMD based), I whitness some very strange and
nasty performance issues with the usage of certain "day-to -day" applications, like Firefox,
LibreWolf, mplayer.

CPU is a current AMD Ryzen (no 3D cache!), 96 GB RAM, GPU is a nVida RX 5060 - with recent
nvidia-driver-580.76.05.1500063 driver version due to issues with the 570 series in ports
tree. X11 window manager is x11-wm/windowmaker. All ports are custom compiled and has been
recently recompiled - these details just for the record.

The phenomenon is when starting Firefox and/or Librewolf, these programs are almost unusable.
Clicking on menus  produce drop down artefacts in the shape of the drop-down-menu when moving
the window. Content of the interior does not change and is frozen and/or doesn't get
refreshed. After several long minutes this misbehaviour seems to mitigate and the program
seems mor responsive. When it comes to video streams, like youtube, the mess is back: streams
are slowed down a way its like a torture watching them. Same with videos in mplayer: playing a
video we made a couple of years ago with Blender (.mkv, .avi) are in slow motion. From time to
time I try my best with warzone2100 - the game also indicates sometimes while in game a sudden
jumpy behaviour or at the beginning. It seems erratic when and how such "jumpiness"  occurs. 

While those applications show up harsh and serious performance problems, the OS itself and
even the X11 windowmaker window system do not indicate any flaw in performance penalties,
which surprises me.

So, I susepct something wrong with either the video subsystem (as mentioned initially, the
in-ports-tree driver nvidia 570 shows some similar problems which could be mitigated by using
the most recent one provided by nvidia, version 580.76.05).

I tried to recompile every single port from scratch due to suspect some ABI issues somewhere
since some critical changes in FreeBSD's core, but this approach didn't help much.

Does anybody else have such problems on the recent CURRENT system and is this well-known (and
so the hope for a solution does not die early) or is this problem sticky with me alone?

Thanks for the patience,

oh

-- 

A FreeBSD user