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.