Hi I'm new in iphone developing. The question is : I have a RootViewController with 2 uibutton. When i execute "memory monitor instrument on my iphone device OS3" RealMemory goes from 3.75M to 4.58M (I launch a uiview1controller by click on one UIbutton, then i close it and return to the RootViewController). When i close then uiview1 then memory goes to 4.22M. Why not to 3.75M? (uiview1controller is a simple test. nothing inside.) if i launch again uiview1controller memory increase from 4.22M and then retunrs to 4.22M. Correct. Then i launch uiview2controller from second uibutton. RealMemory goes from 4.22 to 6.01M. When i close the uiview1controller memory goes to 4.73M. Why not to 4.22? uiview1controller is a simple uiview with 3 uilabel and 3 uiimage designed with InterfaceBuilder and . the ONLY code write from me in uiview2controller is declare 3 iboutlet uitextfield and set uitextfileld text in loading. every time i launch the uiview2controller and close it memory increase of 0.51M ? What's worong? i tried to release iboutlet but it's the same. Thank you very much.