Slight flickering only on dark grey on external display: Why?

[ejosepha]

I have a 28" inch display attached to newest version of Air. Works ok except when I have a full screen on plain dark grey background, then I see a waviness or flickering effect. Like the dark grey in Iphoto background. Other than this, the other colors seems ok. Pictures are fine, even when dark. Maybe there's a slight flickering with dark blue. Any explanations for this.
using mini display port to dvi. Tried with a friends dual link display, was a little different, but still unstable looking in dark grey when it fills the screen.
Could it be just what it takes to make this color, or the Hertz, which is 60.
Other than this, no problem with the screen.

 

[nicorojas]

Are you using the VGA adapter? The same thing happened to me in a 19" Viewsonic external, and then in a 24" Dell.The flickering was most noticeable when the CPU was stressed, like when using VMWare Fusion.

However, it stopped after I switched to the MiniDP-DVI adapter.

 

[ejosepha]

Are you using the VGA adapter? The same thing happened to me in a 19" Viewsonic external, and then in a 24" Dell.The flickering was most noticeable when the CPU was stressed, like when using VMWare Fusion.

However, it stopped after I switched to the MiniDP-DVI adapter.

I am using a mini display port to dvi adaptor. It's strange that it mainly flickers on the dark grey background, which I tested from the desktop plain color choices. On most of the other colors no problem. For example, on the background in iPhoto around the photos the grey shimmies or flickers. But I don't see this on most of the colors. This is a HannsG 28" screen. Not expensive. I have tried both the dvi port on the screen as well as the dvi to HDMI port and it's similar symptom.
Not on black, or most other colors, but dark grey and darker blue. I thought it could be the apple adaptor but I would think that if it were the adaptor that it wouldn't discriminate between colors.