I did a quick test to see how much free memory iPad Air 2 has with 2 GB.
1189 MB free after rebooting.
631 MB free after opening 4 MacRumors forums tabs, taking pictures, locking, left alone for some time, and unlocking.
367 MB free after reopening Safari and tapping on 4 tabs to check if they reloaded which they didn't.
https://twitter.com/iphone5att64/status/525126416992829440
For comparison, after rebooting on iOS 8.0, iPhone 5S had 46.81 MB and iPhone 6 Plus had 39.84 MB free memory.
https://twitter.com/iphone5att64/status/513842656926244864
1189 MB free after rebooting.
631 MB free after opening 4 MacRumors forums tabs, taking pictures, locking, left alone for some time, and unlocking.
367 MB free after reopening Safari and tapping on 4 tabs to check if they reloaded which they didn't.
https://twitter.com/iphone5att64/status/525126416992829440
For comparison, after rebooting on iOS 8.0, iPhone 5S had 46.81 MB and iPhone 6 Plus had 39.84 MB free memory.
https://twitter.com/iphone5att64/status/513842656926244864