if this just happens on games, then, it may not be the monitor. Also, what type of onboard gfx is it?
The onboard graphics is ATI Radeon Express 200. The games I have played are World of Warcraft and Silkroad Online. Before this motherboard I was using a GeForce 4 and had no problems while playing Silkroad (I never tried WoW with the old card because I knew it wasn't fast enough). With the new board I had no problems with Silkroad in the beginning but have been noticing problems as of late with increasing degredation. I do think I know what the problem may be - too much stress on the board from the lack of a backing plate for the cpu fan/heatsink - is one possibility. I've only had the board for 3 weeks and was planning on buying a graphics card, but never expected the onboard graphics to degrade so quickly.
1) What resolution do you use in games and desktop? 2) What refresh rate do you use in both as well? 3) Are you using and LCD (if so which, native resolution)? 4) Are you using a VGA connection? 5) Are you using any anti-aliasing/anistrophy in games?
Edit: Oh yeah, have you checked the actual connections (only would really affect vga) and the temperatures of your chipset as well?