ATI Radeon X1900 XT and Mac Pro sparkling/dancing artifacts

My friend Adam Nash told me today that I'm a "high-maintenance" computer user. I replied that I just want my computers to work. Here's an example: I have a Mac Pro outfitted with an ATI Radeon X1900 XT. When I run certain apps, I get moving pixel artifacts on the screen which can only be described as "sparklies". Individual pixels light up and dance around, always in the same windows and in the same places. Frustrated, I called Apple support, escalated to a Product Specialist, and got a replacement card shipped out. (I also have the NVIDIA GeForce 7300 GT; when I plug in the same monitor with the same cable to that card, no such artifacts appear. This led me to believe that it was a video card issue, since that was the only thing that changed.) Unfortunately, I installed the replacement card today, and the artifacts are still there.

Even more bizarre, when I took a screenshot of Aperture (one of the problem apps) and then opened the screenshot image in Photoshop, the artifacts appeared -- in the same place! That's right: artifacts appear both in Aperture and in screenshots of Aperture.

It gets worse: when I crop the screenshot to only the offending area, the artifacts keep on dancing. Clearly there is a problem with showing a specific combination of pixels. The thumbnail image in this post is a cropped portion of my screenshot, and when viewed in Photoshop or Preview (when placed in specific parts of my screen), I see artifacts dancing around.

The artifacts also persist in every resolution I can set my 30" monitor to display -- even in stretched resolutions.

My friend Douglas recently had the same problem (same hardware combination). He took his Mac Pro to the Genius Bar and left it for a week. When he got the machine back, the problem persisted, so he started unplugging peripherals. Finally, when he unplugged his non-Apple keyboard, the artifacts went away. Unfortunately, I'm using an Apple Bluetooth keyboard, so that solution won't work for me. *UPDATE* Douglas reports that the fix did *not* work.

I'd like to ask a favor. If you have a Mac Pro with the ATI card, can you download the thumbnail in the post, open it in Preview.app, and drag it around your screen? Let me know if you see any artifacts.

NOTE: The thumbnail in this post does NOT display artifacts when viewed with Firefox on the Mac because Firefox doesn't support color management. However, I see artifacts in the image when I view this post using Safari.

*UPDATE* Douglas tells me that a temporary solution seems to be to hit "Detect Displays" in the Displays System Preference. Sparklies go away. But when they come back, you have to do it again. I tried it, and it seems to work!

*UPDATE, POSSIBLE FIX* On October 16, 2007, Apple issued a firmware update for the ATI X1900 XT that seems to have fixed the problem for me. I WAS WRONG. I'm still seeing sparkles in Aperture, but only when I am paging through images in the Viewer. The "dancing" sparkles in gray areas are gone.