I have a 1st gen iPad WiFi and a 1st gen iPad 3G. Both are running iOS 5.1.1. But the animation for closing an app is different. The WiFi one used to have the same animation as the 3G one, but it has since changed to have a trail. Check out the pics to see what I mean.
iPad 3G - Old animation with no trail
iPad WiFi - New animation with trail
It's easier to see when you use the multitasking gesture to close an app so you can control the speed. Which animation does your iPad do?
Note: The 3G iPad is using the last version of Google Earth in that pic, which I've since updated, and it still does the same trail-less animation.
iPad 3G - Old animation with no trail

iPad WiFi - New animation with trail

It's easier to see when you use the multitasking gesture to close an app so you can control the speed. Which animation does your iPad do?
Note: The 3G iPad is using the last version of Google Earth in that pic, which I've since updated, and it still does the same trail-less animation.