Question / Help Quick Sync duplicating and skipping lots of frames

[duzy_wonsz]

https://gist.github.com/8cd0e19a13c6d2e50fd2

Sory for not writing too much, but I will give more info tomorrow.
Assetto Corsa 1080p60fps (Playing at 80FPS+) seems to make Quick Sync drop and duplicate lots of frames.
Recording CS:GO (which plays at 1280x720 and 300FPS) seems to work fine though.
Any first thoughts?

RivaTuner seems to show about 70-80% GPU2 (HD 4600) usage and 218-220MB of VRAM consumed by GPU2.

 

[duzy_wonsz]

I've tried increasing shared memory with iGPU and clocking it 100MHz+, but it doesn't help, also disabling QS custom parameters. Nothing helps.

Here is a new log. What is going on.

Edit:
Well, I've lowered bitrate to 10K that gave me 0.32% of duplicated frames.
Then I went even lower to 5K that gave me over 3% of duplicated frames.
What?