Reproduction steps:
1. Open User's projects
2. Build to iOS
3. Deploy to device
4. Look at Debug navigator
5. Look at memory usage
6. Capture GPU frame

Expected behaviour: Memory and GPU usage ate similar through different versions.
Actual result: Memory usage increases by 4-7MB and GPU usage by <1ms

Same results on graphics API: GLES3, Metal

Performance is worse on versions: Unity 5.5.1p4, 5.6.0b9
Performance is little worse on version: 5.4.4p3
Performance base: 5.4.2f1
Reproduced on devices: iPhone 6 iOS 10.2.1, iPhone SE iOS 9.3