I would like to ask the question like this: does the 64 bits support mean i will have to purchase 64 bits machines for my CS5 copy?
Thank you for your helps.
Yes, you will need to have a 64-bit operating system and a 64-bit processor.
For Mac OS, Leopard (10.5) and Snow Leopard (10.6) are already capable of running 64-bit applications, and any Macintosh sold in the last few years can run 64-bit software.
For Windows, you need 64-bit Windows 7 or 64-bit Windows Vista.
For system requirements, see this page:
You'll also need to upgrade all your plugins to 64bit.
You can check here to see if your favorite plug is announced for CS5/64bit: http://www.yenaphe.info/cs5-update-guide/
Thanks for that link, Sébastien!