dim pc monitor

I have just recently aquired a 530 card myself, I am currently using a radius Dos on PPC card in my nubus 7100/80. I have experienced poor monitor conditions when using adapters wich allow me to use my pc monitor with my mac while also using the pc cards monitor cables. This would affect the monitor in the mac environment as well. could this be your problem?
I am currently toying with different settings on my monitor adapter mac/pc-monitor, and considering purchasing a mac monitor to cut out this adapter period.