This topic describes the memory limits for supported Windows and Windows Server releases.
Limits on memory and address space vary by platform, operating system, and by whether the IMAGE_FILE_LARGE_ADDRESS_AWARE value of the LOADED_IMAGE structure and 4-gigabyte tuning (4GT) are in use. IMAGE_FILE_LARGE_ADDRESS_AWARE is set or cleared by using the /LARGEADDRESSAWARE linker option.
4-gigabyte tuning (4GT), also known as application memory tuning, or the /3GB switch, is a technology (only applicable to 32 bit systems) that alters the amount of virtual address space available to user mode applications. Enabling this technology reduces the overall size of the system virtual address space and therefore system resource maximums. For more information, see What is 4GT.
Memory and Address Space Limits
The following table specifies the limits on memory and address space for supported releases of Windows. Unless otherwise noted, the limits in this table apply to all supported releases.
| Memory type | Limit on X86 | Limit in 64-bit Windows |
|---|---|---|
| User-mode virtual address space for each 32-bit process | 2 GB
Up to 3 GB with IMAGE_FILE_LARGE_ADDRESS_AWARE and 4GT |
2 GB with IMAGE_FILE_LARGE_ADDRESS_AWARE cleared (default)
4 GB with IMAGE_FILE_LARGE_ADDRESS_AWARE set |
| User-mode virtual address space for each 64-bit process | Not applicable | With IMAGE_FILE_LARGE_ADDRESS_AWARE set (default):
x64: 8 TB Intel Itanium-based systems: 7 TB Windows 8.1 and Windows Server 2012 R2: 128 TB 2 GB with IMAGE_FILE_LARGE_ADDRESS_AWARE cleared |
| Kernel-mode virtual address space | From 1 GB to a maximum of 2 GB with 4GT | 8 TB |
