So i disabled TDRs (rebooted and checked that it is disabled) but the blackouts did not stop.
I also checked the windows stability journal and there was nothing particular - just igfxcuiservice "has stop working" error that has been occurring from the day i build the system 2.5 years ago. The only peculiar thing about it is that if a week ago it was named in the journal as "igfxcuiservice.exe" then after i reinstall the driver for the last time it suddenly changed to "igfxcuiservice module" error. My problem is a month old so it is probably irrelevant to it, just strange.
-----------update: it was my monitor after all.