Based on your description It seems that the cable or the adapter you are using may be causing the problem.
I recommend you doing the following:
1. Install the latest graphics driver that can be downloaded at the following link:
2. Test a different analog adapter or if possible an active adapter. There may be adapters that due to the quality the performance can be affected.
3. Test a direct connection between your computer and the monitor.
Sorry about the really late delay.
I think it is something to do with the monitors and not the integrated graphics. Maybe some kind of external interference? But that wouldn't have anything to do with my Intel graphics so I don't expect you to help me any further.
I'm going to mark your answer as the right one as it is the most common steps for troubleshooting.
Thanks for your time.