Playback with GUI olverlay on S912 is not fluid

Hi all
What I am experiencing is a choppy playback with GUI overlay (playback controls or GUI is the same) on S912 while on S905X with the same CE 8.95.2 is ok
It is nothing dramatic but noticeable. This question may already have a final answer due to the known limitation of the OpenGL stack which run on top of libhybrid on S912, but I wanted to know if there is something I can do to mitigate or fix it

You can change dirtyregions and overclock the GPU, it might help improve things but the temperatures will go up.

with dirty regions set to 0, everything is smooth now (including the start of subtitles rendering).
Why this is not set as default for amlogic?

We did this once a few versions ago, unfortunately it increases the SoC temperature when at the GUI and everyone started complaining so we reverted the change.

Is it happening also for S912? Because this is required by S912, S905x run ok except when the first subtitles is rendered.
I mean, if the SoC is going to burn is a story, but if it is “just” hotter, without dirty region S912 is unusable for GUI and subtitles overlay, just it

It usually runs 5-10C hotter when idle when in Kodi GUI.

With proper box/cpu cooling, it’ not a problem. On my X92 box, with a slightly bigger CPU Cooler, it raise the idle temps only 4-5°C (from 49 to 54°C).
There is no temperature rise when playing any kind of files, only in idle.