Old inxi or old kernel?
5.14.14 is last one
KDE use more CPU power than i3wm/Xfce, but my old i7 3770K with NVIDIA GeForce GTX 1060 6Gb, 16 GB RAM stutter only if I render pictures with Blender.
https://www.mail-archive.com/kde-bugs-dist@kde.org/msg556107.html
https://www.mail-archive.com/kde-bugs-dist@kde.org/msg587597.html
kwin_core: XCB error: 10 (BadAccess)
On the other hand the MJ solution