Radeon X1900 hits image quality snag in 3DMark06

During the preparation of my Radeon X1900 review, I discovered a problem with Radeon X1900 cards in 3DMark06. I meant to mention it in the review itself, but things came down to the wire and I just ran out of time. Here's the deal: in the "Firefly Forest" scene of 3DMark06, Radeon X1900 cards render an image that's not quite right. The problem is visible to the naked eye—that's how I spotted it. The glowing area around the two floating lights in that scene—the "fireflies," I suppose—looks almost as if the colors were dithered on the Radeon X1900. Like most dithering, this visual artifact is most obvious in motion; the area around the lights creeps, crawls, and "fizzes" as the light moves through the scene.