Rytr and I have been exploring the flickering issue. Neither Rytr nor I have experienced any flickering in Windows or games until Rytr noticed some flickering with the bar chart displayed from Ben's Custom Cases UT2K3Bench program. Rtyr has a Creative Labs 3D Blaster FX 5900 Ultra and a PowerColor 9800Pro while I have a BFG FX 5900 Ultra and an ATI All-In-Wonder 9800Pro. On all four of these cards (both ATI and NVIDIA)
both Rytr and I have noticed obvious flickering on this UT2K3Bench chart. The flickering varies from horizontal flashing bars flashing very quickly (on Rytr's system) to more of an isolated square again flashing very fast in what appears to be somewhat of a checkerboard pattern on my system.
Below is a photo (that I took with my digital camera) showing this effect. It's fairly obvious in the first bar chart group on left going across the top half of blue and yellow chart. NOTE: This photo was taken with my AIW installed in my machine. The same effect was present with 5900Ultra as well.
I've also included a negative area and zoomed 200% of this area in image below this post to further identify this flicker effect. NOTE: I took close to 100 photographs of my monitor and this was the ONLY photo that came out showcasing the flicker effect. This shows how fast the flicker occurs and how lucky I was to trap it in a photo!