can 32 bit programs utilize more memory while running in 64 bit environment??

Hi..s,

I am not a professional coder and i do not have in-depth knowledge about memory addressing. Recently i have decided to upgrade my Window 7 to 64bit. Now i have a doubt that whether a 32 bit program can utilize more ram memory (i.e. >4GB) while running in 64 bit environment? If so, any performance improvement will be notified in real time usage.?!?.