So I'm about to finally go to a 64 bit operating system and I'm just wondering do I need to re download Sonar X2 or will the version of X2 I downloaded for my 32 bit operating system recognize its 64 bit.
 
Cheers Ben

The X2 installers contain both the 32bit and 64bit versions of SONAR however; it is necessary to run the installer and specify which version to install. It is possible to install both the 32bit and 64bit versions (by running the installer two times) on 64bit Windows because they install in different locations. If old projects relied on 32bit DX plug-ins, it may be necessary to install the 32bit version because many of the old 32bit DX effects were not ported to 64bit. Unlike VST plug-ins there is no software bridge for DX plug-ins.

You will need to install the 64 bit version if you want that version. Both can run on a 64 bit OS. But only the 32 bit version can install and run on a 32 bit OS. The 32 bit version running under a 64 bit OS will still run in a maximum of 4 GB of memory. Where the 64 bit version will be able to access all the memory you have. 
 
You will also need 64 bit drivers for every device. 

Thanks

Cheers.

One other thing to consider.  Some number of 32-bit plugins will run in a 64-bit Sonar, with no problem.  They will be loaded through a connective piece of software called BitBridge (or you can go buy something called JBridge).  Some 32-bit plugins will NOT play nicely in a 64-bit Sonar with BitBridge OR with JBridge.
 
This is why I always leave a 32-bit Sonar installed, so that I can access projects that were created in 32-Bit Sonar, or need 32-bit plugins that don't work in 64-bit Sonar.
 
I would recommend you check for 64-bit plugin updates for your current 32-bit plugins, as 64-bit plugins are likely to work better in 64-bit Sonar.  These are usually free updates, and this is well worth doing.
 
I DO have a couple of freeware 32-bit plugins that I do access frequently in 64-bit Sonar (they work and I like them), and for these, I moved them to a new sub-folder within my VST Plugins folder for my other 32-bit plugins.  I then added only this sub-folder to the search path in 64-bit Sonar.  This way, only 32-bit plugins that I know will work in 64-bit Sonar are available to it, and because the 32-bit Sonar will automatically see the sub-folder, one copy of them is shared across both Sonars.
 
Good luck, and welcome to 64-bit processing.
 
Bob Bone