Memory usage on older devices is much higher seems to be reproducible on iPad 4 and older devices.

To Reproduce:

1. Build & Deploy the attached project with Unity 4.6
(you can use the project from http://fogbugz.unity3d.com/default.asp?722868 the memory difference there is much larger, but it takes a while to build it).
2. Observe in Xcode that memory usage is higher on older devices, it was about ~5.2mb with this project, but using the one from 722868
(after deploying start the game from the menu) :

iPad 2 - out of memory
iPad 3 - 435mb
iPad air 1 - 244mb
iPhone 6+ - 227mb

It looks like that that there is a very large number of small allocations on older devices (VM Tracker in Instruments)
for example on iPad 3 there are 1033 dirty #regs while on Air 1 it's only #278 (see attached text files with allocations)
while all large ones are more or less similar in size (see screenshot)
Comparison was done with 722868 project's menu scene (it crashes due to out of memory on iPad 3 in game scene if instruments are attached)

Issue is only reproducible on 4.6.x (tested 4.6.9f1)