It wasn't until I started upgrading all of the LibreElec units I have (and have distributed to friends/family) that I noticed that 'video acceleration' was enabled for the on-board graphic processors that never had it (and were reaching 99% CPU usage for 4K 'high quality' video streams).
VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RS880 [Radeon HD 4200]
I'm seeing approximately 25-33% less CPU usage (see images) with the VAAPI acceleration enabled.
BUT, I have also found that the acceleration is DIS-abled after the unit(s) have 'gone to sleep' (suspend mode) and been re-awakened. Only a reboot of the system re-enables the acceleration abilities...
The problem is sometimes more obvious, with a 'lockup' of the GUI when Kodi comes out of 'suspend mode', with a strange artifact in the middle of the display (see images), and then either a 'reset' of the desktop, or a restart of Kodi (without rebooting), with either action resulting in the disabling of video acceleration.