exiting Running programs, getting the peal affect

[itouch24]

i currently have 202.9M of memory and 128.7M of RAM available on my HTC touch pro...

when i try to run or close a program i am getting like a peal affect for previous program to close... whole screens arent dropping nice and clean.. just piece by piece

for example... i hit the start button.. start menu pops up all at once..

then i hit calculator and the bottom portion on the start menu disappears but about the first 10 pixels of the start menu stay on screen for a few seconds.. then it goes away and i see the windows wait cursor then i see calculator pop up.. why am i getting this lag... why doesnt start menu drop quick when i select an applcation... instead it drops off screen in two steps....??

any ideas... i have plenty of ram .. not sure why such a lag

i am running the default sprint ROM on device from factory