FreeBSD 13.2-RC1 FPS in screensaver drops after hours

FreeBSD 13.2-RC1 FPS in screensaver drops after hours

Hi all! Sorry for my bad English...

I have access to several computers running FreeBSD 13.2-RC1 and Intel 
(U)HD Graphics. For example, it is an Intel NUC7PJYH (Intel J5005) and 
an Acer Revo Box RN86 (Intel Core i5-9400T). Additionally, I can 
experiment with Intel NUC5PPYH (Intel N3700) and Acer Aspire XC-895 
(Intel Core i5-10400) if needed.

I am using Xfce 4.18, drm-510-kmod video driver (installed from pkg or 
built from ports). Xfce uses xscreensaver and Ant Inspect screensaver 
with FPS counter and CPU Load counter enabled.

Normally the FPS value is FPS 40 and CPU Load 15%, but if the 
screensaver has been running for several hours the FPS can drop to about 
FPS 18. The CPU Load value also increases.

All serious applications were terminated before the screensaver was 
turned on.

Powerd is on by default on these computers, I can try to turn it off.

I have not noticed this problem in previous releases of FreeBSD.

Could this situation indicate a problem with FreeBSD's graphics subsystem?

P.S. FreeBSD 13.2-RC2 will be available soon and I will do more detailed 
experiments with it, and bring stats and FPS screen shots.