SOLVED: Bad transcoding performance using Intel UHD 770

[fl0wfr]

I finally found the cause of the issue, I set the BIOS CPU C-States to C10, it may not be properly implemented in the BIOS.
After setting it to Cpu Default, I get this result:
Decoding (VCS at 50% in intel_gpu-top):

Code:

frame=10207 fps=295 q=-0.0 Lsize=N/A time=00:07:05.75 bitrate=N/A speed=12.3x

Encoding (VCS at 50% in intel_gpu_top):

Code:

frame= 2413 fps=109 q=-0.0 Lsize=N/A time=00:01:36.36 bitrate=N/A speed=4.35x

I guess this matches with the ability to transcode 4 4K videos simultaneously.
Thanks for your help!