Didn’t even noticed this earlier , but why HTOP show that there is 804 MB RAM.
Where is the rest 196 MB from 1GB…?

GPU/VPU shared memory.

You can disable GPU/VPU memory by running dietpi-config > Display Options > GPU/RAM Memory Split > Server

I see.
I use sometimes VNCserver . and Kodi as head throu HDMI.

Is VPU must be enabled ? or it can be set as Server ( HDMI en, VPU disable) ?
VPU is essensial to render movies/kodi ?

For a server only operation, you can disable both to get more free RAM.

Please have a look:



HW video deconding with C1