I'm confused. The ISO 1000 shot on that site looks similar to maybe ISO 500 or 600 on my D70, and the ISO 6400 shot looks pretty close to what ISO 1600 can look like when underexposed on my D70.. except the noise pattern looks a lot cleaner and easier to work with. What's the issue? I'm sure the 40D is better with its high ISO noise but the OP is kind of making it sound like there's almost no improvement
