1600 has an almost film grain like noise. It isn't softer, or smeared, just a bit more grainy. Not unpleasantly noisy though. It would print really well.

If you look at the maroon leash of the dog, you can still see all the detail of the webbing. Some of the shots of them running were a bit less focused because I couldn't get the shutter speed up enough to get to 1/1000, where it really stops the action. I probably should have tried 3200 ISO. duh!

Here is a 100% crop. It is straight from the camera and no sharpening done on it