Black patches after time : Billabs Autosync Monitor BL25C90T

[znottaken]

A few of my cohorts and I are working on an arcade machine using a standard ATX motherboard, however after getting everything set up how i want it with HyperSpin, MAME and the works along with an Arcade VGA5000, which seems to be working pretty well. The issue that i'm having is that after five or ten minutes or so my screen will begin to show continuously darkening patches. They get darker as time goes by, and they don't persist after a reboot though they do come back. I would appreciate some help as to why this is happening and some tips or steps as I could use to help resolve the issue. Thanks in advance for your help.