We have a lot of users accessing our CRM on iPad and other platforms without any issues of slowness.
It very much sounds like an Apple issue not a CRM issue. You could try pressing Command R to refresh the cache just in case it is a reloading of page issue.
Here are a couple of links on the Apple discussion forum describing slowness for iPad 3 - they seem to be suggesting could be to do with battery drain:
https://discussions.apple.com/thread/5325977
https://discussions.apple.com/message/23024024#23024024
We would suggest you contact Apple Support direct which in the UK is: 0800 048 0408 as they should be able to shed further light on what is causing this issue.