ask yourself does 64 bit bring any + for you??
guess not really, unless your not using any samplers which require lots of ram then forget it, i think 64 Bit is just a big Promotion Joke
i have a ti 2 on windows 7 32 bit, Intel Quadcore, that´s more than enough power
and if you still need 64 Bit:
Presonus Studio One
HIGH-END AUDIO ENGINE
Studio One is based on a cutting-edge audio engine that delivers unparalleled sound and automatically
switches between 32-bit and 64-bit floating-point processing on the fly (even with a 32-bit OS), ensuring the highest quality audio at all times.
http://www.presonus.com/products/Sof...?SoftwareId=11
so you don´t really need 64 bit OS
also things could go new ways in Windows 8