Acer*
Are you using an HDMI cable or VGA?
EDIT: I'll just put my thoughts here now. I've seen the effect you're talking about with lower quality or very long runs of VGA cable. Though, I've only had it happen on 35ft+ VGA cables. Plus, if you can only see it on that test, it should be fine. I'm running DP to VGA, as well as HDMI to VGA adapters and see it on that test, but no where else ever.