64 Bit Windows

While Vectorworks is fully supported in both 32 bit and 64 bit Windows environments, we generally recommend using a 64 bit Windows operating system for Vectorworks 2011.

While Renderworks is fully supported in both 32 bit and 64 bit Windows environments, we strongly recommend using a 64 bit Windows operating system for Renderworks 2011, as it will take full use of 64 bit addressing.

With those recommendations having been made, we have noticed that drivers for 64 bit Windows can be somewhat more problematic than those for the more mainstream 32 bit versions of Windows. Should you choose to run 64 bit Windows you should make sure that you carefully choose your hardware and driver versions to avoid problems.

64 Bit Mac

The current iterations of Mac OSX (10.5 and 10.6) are both 64bit operating systems.

Microsoft 64bit FAQ

http://windows.microsoft.com/en-US/windows-vista/32-bit-and-64-bit-Windows-frequently-asked-questions

Macintosh 64bit FAQ

http://www.apple.com/macosx/technology/64bit.html
http://support.apple.com/kb/HT3770