How to set up Quick Sync?

Question

Intel

I have an i5 4670 processor and a GeForce 750 Ti on Win 10. I want to write video from the screen through OBS in 1080p with 60 FPS. 60 FPS, unfortunately, slows down (the video itself twitches every few seconds), 30 pulls perfectly. Advised to enable QuickSync.
Actually, I enabled "multiple screens" in the BIOS, expanded the screen by 2 (virtual display), go into the display settings, click "detect" and I see there display 1 (real) and a second display (virtual) with the inscription "display not defined" . Save nothing, of course, does not work.
Actually, how can I make the virtual display become defined? In Google I found only troubles with connecting a second monitor / TV / microwave.