Unity iphone - texture upload speed

I need to perform some pixel effects on my textures (no, shaders will not work) and I need to perform SetPixels and then upload my texture every frame.

So, I’m interested how fast such upload will be on iPhone (let’s say, iPhone 4).

The texture size is about 2048x2048 and there’s only one texture I need to update.

PS: Please, do not suggest me use some other methods and so on. I just need to know the real hardware performance while doing large texture upload to GPU.

I built an application where I attempted to upload a 1024x1024 texture to the screen at realtime on the iPad 1. It was unusably slow (2 or 3 frames per second), so I changed to tiled textures (16 128x128 textures taking the same space as the original 1024x1024 texture) and only update the tiles that get changed that frame.