You should use whichever option best suits the OS and specific memory needs that your application has. The majority of LabVIEW toolkits and modules support LabVIEW 64-bit. See LabVIEW 32-Bit and 64-Bit Compatibility for further discussion.
LabVIEW 2009 was the first release with a 64-bit version.
Through LabVIEW 2013 SP1, only Windows Operating Systems were supported. LabVIEW 2014 64-bit added support for Linux and Mac OS X. Detailed information about the supported Operating Systems for each version can be found in LabVIEW Operating System Support, Windows Version Compatibility with LabVIEW, LabVIEW 2014 Readme for GNU/Linux and LabVIEW 2014 Readme for OS X.
LabVIEW 64-bit does not support all of the toolkits supported by LabVIEW 32-bit. This support also varies by operating system:
Each article has information about LabVIEW Add-Ons, Toolkits and Drivers for each Operating System.
Every customer who purchases LabVIEW 2009 or later has a license for both the 32-bit and 64-bit versions.
The LabVIEW 64-bit installer is available on the LabVIEW Platform DVD for Mac OS X only. The Windows installer can be downloaded via the LabVIEW 64-bit section of our website. LabVIEW 64-bit for Linux is only distributed on a DVD; contact your account representative if you require a copy of LabVIEW 64-bit for Linux.
Yes, a VI that is written with LabVIEW 32-bit development system can be opened in LabVIEW 64-bit and vice versa because the code is not compiled until the VI is run.
No, you cannot run the LabVIEW 64-bit Development System, Run-Time Engine, executables or applications on a 32-bit computer.
In a Windows environment, you can run 32-bit executables on a 64-bit PC and therefore, the LabVIEW 32-bit Development System, Run-Time Engine and executables can run on a Windows 64-bit computer. A Mac OS X computer running a 64-bit kernel cannot run 32-bit applications; switching to a 32-bit kernel will be required to run a 32-bit application and whether the kernel can be switched is dependent on the Mac OS X version. Linux 64-bit requires the installation of 32-bit libraries to run 32-bit applications; however, installing these libraries does not grant all 32-bit applications will run on 64-bit Linux computers.
No. Currently, there is not an option to create a 32-bit version of an executable from the LabVIEW 64-bit application builder.
An application can request memory, but it is up to the Operating System to accept or deny that request based on what is available (either physical or virtual). LabVIEW 32-bit on Windows XP 32-bit, by default, can only use up to 2 GB of address space. There is a 3 GB boot option that can allow applications on Windows XP 32-bit to use up to 3 GB of address space. LabVIEW 32-bit running on Windows Vista 64-bit Windows 7 64-bit can use up to 4 GB of address space. In any of these configurations you can still run into large buffers failing to allocate if enough contiguous memory is not available. LabVIEW 64-bit on an 64-bit Operating System supports as much RAM as the Operating System supports (theoretically, 16 exabytes). Currently, 64-bit Windows imposes a 16 TB limit.