Monitor display gets grainy, what could be the cause?

Dante_Abyssal

Commendable
Oct 14, 2016
1
0
1,510
So have an LG monitor that only has vga input, it used to work just fine, but with my new system, it gets slightly grainy, especially with dark colors, I tried displaying through HDMI cable (other monitor) it works fine, tried another system in my LG & it also works fine, it's like my unit and monitor don't like each other. I also tried other cables which gave me worse results... but I noticed that the grains come and go.
any advice? thank you