I have just made a quick test. A simple scene with an image and a sound.
Exported with Unity3.4.2 and with Unity3.5.2
Both export come from the exact same project folder.
We are talking on how long the users will see the Unity splash screen before to enter the game (basic users).
Or, for PRO users, we are talking on how long users will see your special splash screen before to enter the game ( I guess as I don’t ow the pro).
Unity3.4.2 build has a fantastic load time of 0.84 seconds (less than one second) then I see my scene popping out.
Unity3.5.2 loaded in more than 5 seconds ! This is not acceptable !!!
Most users on iPad2 after 3-4 seconds of the Unity splash screen will think the game is broken or something.
Why this changed so much in 3.5 ?
I mean less than one second compared to 5 seconds is an eternity, why ?
It’s ok that less than one second doesn’t show enough Unity Logo, and I can live with this choice, but why making the initial engine load or splash screen wait so long ? Was not enough 2 seconds ?
Also the framerate is much worse with 3.5, and we are not using fancy shaders or real time lights, just a simple directional light. But where we get 40-50 fps now we get 23-39, this is bad, so bad.
We can’t believe our eyes. Because now WE MUST use 3.5.2 the only version able to deploy a submittable binary, this is so bad…
My project that I’m going to submit in 2 weeks or so is built on 3.4.2f Pro, why can’t I submit with that?
I recently resubmitted a game previously on 3.4.2 in 3.5.2 and i didn’t notice a drop in frames… What iOS are you targeting? (I was using SDK 5.0, targeting 3.2)
Be sure to check the unity xcode profiler to see what the bottleneck might be…
One trick to get around a big initial load is to make your title screen a stripped down scene. (So at least the initial load is quick…)
You can because you have Pro. So you can change the splash screen.
Basic users won’t be able to as I doubt Apple will approve an iPad (or universal) App that is not supporting the 2048x1536 iPad3 splashscreens.
I’m doing this 5.1 targeting 3.2 but still the load time got 5x and framerate dropped a LOT !
This is exactly the point, please read again my initial post carefully:
Hmm… have you checked the xcode profiler option?
I have not this option as I am a Basic user.
The only things that bugs me is that those 2 tests were development(debug) builds, and on the 3.5.2 one built on xCode 4.2 on Snow Leopard with base SDK 5.0 I noticed on the console log a trial to connect to debugger on address 0.0.0.0, it might be this trial to connect that slows down so much the 3.5.2 debug build in comparison to the 3.4.2 debug build ?
I’ll make a release builds comparison and I’ll update this thread once completed.
Whaaaarg dumb me!
I have to apologize to UT for my last rant.
It was indeed the new debug connection slowing down the starting time.
The reason why the engine load time got 10 seconds while building&run and 5-6 seconds on device detached was of course the build of a debug binary 
Sorry, it was a long time I didn’t build on iOS and I forgot the basics 
I must admit that also the 33° we got in Italy these days are not helping at all.
It still performs worse, talking about the framerate with 3.5.2 compared to 3.4.x though
I will make more tests with the release and report later.
l don’t understand why the DEBUG compiled with 3.4.x had a short load time but I think it has something to do with the new debugger used on iOS5 ?