Ios problem...

[thedarkgod]

This really sounds like a setting related issue, I would recommend disableing any sort of filtering and scaling, enabling the cheats and mipmapping, and making sure fast memory is enabled.
There is a thread detailing how you can improve you performance in greater detail, which I sadly can't link to since i'm on my phone.

If your issues are still not resolved I would usually recommend going through all builds manually, but since ios is not supported by the buildbot that might be somewhat hard.
If someone has provided you with the builds, going through that persons library might help single out the issue.
The thing is, between the two major builds there have been multiple changes, and if you can't single out the cause of the issue, or get someone with a similar issue to help you single it out, it will be a huge pain to fix, if the problem can even verified.