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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.
Limits on physical memory for 32-bit platforms also depend on the Physical Address Extension (PAE), which allows 32-bit Windows systems to use more than 4 GB of physical memory.
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: Windows8.1 and Windows Server2012R2 or later: 128 TB x64: Windows 8 and Windows Server 2012 or earlier 8 TB Intel Itanium-based systems: 7 TB 2 GB with IMAGE_FILE_LARGE_ADDRESS_AWARE cleared |
| Kernel-mode virtual address space | 2 GB From 1 GB to a maximum of 2 GB with 4GT | Windows8.1 and Windows Server2012R2 or later: 128 TB Windows 8 and Windows Server 2012 or earlier 8 TB |
| Paged pool | 384 GB or system commit limit, whichever is smaller. Windows8.1 and Windows Server2012R2: 15.5 TB or system commit limit, whichever is smaller. Windows Server2008R2, Windows7, Windows Server2008 and WindowsVista: Limited by available kernel-mode virtual address space. Starting with WindowsVista with Service Pack1 (SP1), the paged pool can also be limited by the PagedPoolLimit registry key value. Windows Home Server and Windows Server2003: 530 MB WindowsXP: 490 MB | 384 GB or system commit limit, whichever is smaller Windows8.1 and Windows Server2012R2: 15.5 TB or system commit limit, whichever is smaller. Windows Server2008R2, Windows7, Windows Server2008 and WindowsVista: 128 GB or system commit limit, whichever is smaller Windows Server2003 and WindowsXP: Up to 128 GB depending on configuration and RAM. |
| Nonpaged pool | 75% of RAM or 2 GB, whichever is smaller. Windows8.1 and Windows Server2012R2: RAM or 16 TB, whichever is smaller (address space is limited to 2 x RAM). WindowsVista: Limited only by kernel mode virtual address space and physical memory. Starting with WindowsVista with SP1, the nonpaged pool can also be limited by the NonPagedPoolLimit registry key value. Windows Home Server, Windows Server2003 and WindowsXP: 256 MB, or 128 MB with 4GT. | RAM or 128 GB, whichever is smaller (address space is limited to 2 x RAM) Windows8.1 and Windows Server2012R2: RAM or 16 TB, whichever is smaller (address space is limited to 2 x RAM). Windows Server2008R2, Windows7 and Windows Server2008: 75% of RAM up to a maximum of 128 GB WindowsVista: 40% of RAM up to a maximum of 128 GB. Windows Server2003 and WindowsXP: Up to 128 GB depending on configuration and RAM. |
| System cache virtual address space (physical size limited only by physical memory) | Limited by available kernel-mode virtual address space or the SystemCacheLimit registry key value. Windows8.1 and Windows Server2012R2: 16 TB. WindowsVista: Limited only by kernel mode virtual address space. Starting with WindowsVista with SP1, system cache virtual address space can also be limited by the SystemCacheLimit registry key value. Windows Home Server, Windows Server2003 and WindowsXP: 860 MB with LargeSystemCache registry key set and without 4GT; up to 448 MB with 4GT. | Always 1 TB regardless of physical RAM Windows8.1 and Windows Server2012R2: 16 TB. Windows Server2003 and WindowsXP: Up to 1 TB depending on configuration and RAM. |
Physical Memory Limits: Windows 11
The following table specifies the limits on physical memory for Windows11.
| Version | Limit on X64 | Limit on ARM64 |
|---|---|---|
| Windows11 Enterprise | 6 TB | 6 TB |
| Windows11 Education | 2 TB | 2 TB |
| Windows11 Pro for Workstations | 6 TB | 6 TB |
| Windows11 Pro | 2 TB | 2 TB |
| Windows11 Home | 128 GB | 128 GB |
Physical Memory Limits: Windows 10
The following table specifies the limits on physical memory for Windows10.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| Windows10 Enterprise | 4 GB | 6 TB |
| Windows10 Education | 4 GB | 2 TB |
| Windows10 Pro for Workstations | 4 GB | 6 TB |
| Windows10 Pro | 4 GB | 2 TB |
| Windows10 Home | 4 GB | 128 GB |
Physical Memory Limits: Windows Server 2016
The following table specifies the limits on physical memory for Windows Server2016.
| Version | Limit on X64 |
|---|---|
| Windows Server2016 Datacenter | 24 TB |
| Windows Server2016 Standard | 24 TB |
Physical Memory Limits: Windows 8
The following table specifies the limits on physical memory for Windows8.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| Windows8 Enterprise | 4 GB | 512 GB |
| Windows8 Professional | 4 GB | 512 GB |
| Windows8 | 4 GB | 128 GB |
Physical Memory Limits: Windows Server 2012
The following table specifies the limits on physical memory for Windows Server2012. Windows Server2012 is available only in X64 editions.
| Version | Limit on X64 |
|---|---|
| Windows Server2012 Datacenter | 4 TB |
| Windows Server2012 Standard | 4 TB |
| Windows Server2012 Essentials | 64 GB |
| Windows Server2012 Foundation | 32 GB |
| Windows Storage Server 2012 Workgroup | 32 GB |
| Windows Storage Server 2012 Standard | 4 TB |
| Hyper-V Server 2012 | 4 TB |
Physical Memory Limits: Windows 7
The following table specifies the limits on physical memory for Windows7.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| Windows7 Ultimate | 4 GB | 192 GB |
| Windows7 Enterprise | 4 GB | 192 GB |
| Windows7 Professional | 4 GB | 192 GB |
| Windows7 Home Premium | 4 GB | 16 GB |
| Windows7 Home Basic | 4 GB | 8 GB |
| Windows7 Starter | 2 GB | N/A |
Physical Memory Limits: Windows Server 2008 R2
The following table specifies the limits on physical memory for Windows Server2008R2. Windows Server2008R2 is available only in 64-bit editions.
| Version | Limit on X64 | Limit on IA64 |
|---|---|---|
| Windows Server2008R2 Datacenter | 2 TB | |
| Windows Server2008R2 Enterprise | 2 TB | |
| Windows Server2008R2 for Itanium-Based Systems | 2 TB | |
| Windows Server2008R2 Foundation | 8 GB | |
| Windows Server2008R2 Standard | 32 GB | |
| Windows HPC Server 2008 R2 | 128 GB | |
| Windows Web Server 2008 R2 | 32 GB |
Physical Memory Limits: Windows Server 2008
The following table specifies the limits on physical memory for Windows Server2008. Limits greater than 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on X64 | Limit on IA64 |
|---|---|---|---|
| Windows Server2008 Datacenter | 64 GB | 1 TB | |
| Windows Server2008 Enterprise | 64 GB | 1 TB | |
| Windows Server2008 HPC Edition | 128 GB | ||
| Windows Server2008 Standard | 4 GB | 32 GB | |
| Windows Server2008 for Itanium-Based Systems | 2 TB | ||
| Windows Small Business Server 2008 | 4 GB | 32 GB | |
| Windows Web Server 2008 | 4 GB | 32 GB |
Physical Memory Limits: Windows Vista
The following table specifies the limits on physical memory for WindowsVista.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| WindowsVista Ultimate | 4 GB | 128 GB |
| WindowsVista Enterprise | 4 GB | 128 GB |
| WindowsVista Business | 4 GB | 128 GB |
| WindowsVista Home Premium | 4 GB | 16 GB |
| WindowsVista Home Basic | 4 GB | 8 GB |
| WindowsVista Starter | 1 GB |
Physical Memory Limits: Windows Home Server
Windows Home Server is available only in a 32-bit edition. The physical memory limit is 4 GB.
Physical Memory Limits: Windows Server 2003 R2
The following table specifies the limits on physical memory for Windows Server2003R2. Limits over 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| Windows Server2003R2 Datacenter Edition | 64 GB (16 GB with 4GT) | 1 TB |
| Windows Server2003R2 Enterprise Edition | 64 GB (16 GB with 4GT) | 1 TB |
| Windows Server2003R2 Standard Edition | 4 GB | 32 GB |
Physical Memory Limits: Windows Server 2003 with Service Pack 2 (SP2)
The following table specifies the limits on physical memory for Windows Server2003 with Service Pack2 (SP2). Limits over 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on X64 | Limit on IA64 |
|---|---|---|---|
| Windows Server2003 with Service Pack2 (SP2), Datacenter Edition | 64 GB (16 GB with 4GT) | 1 TB | 2 TB |
| Windows Server2003 with Service Pack2 (SP2), Enterprise Edition | 64 GB (16 GB with 4GT) | 1 TB | 2 TB |
| Windows Server 2003 with Service Pack 2 (SP2), Standard Edition | 4 GB | 32 GB |
Physical Memory Limits: Windows Server 2003 with Service Pack 1 (SP1)
The following table specifies the limits on physical memory for Windows Server2003 with Service Pack1 (SP1). Limits over 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on X64 | Limit on IA64 |
|---|---|---|---|
| Windows Server2003 with Service Pack1 (SP1), Datacenter Edition | 64 GB (16 GB with 4GT) | 1 TB | 1 TB |
| Windows Server2003 with Service Pack1 (SP1), Enterprise Edition | 64 GB (16 GB with 4GT) | 1 TB | 1 TB |
| Windows Server 2003 with Service Pack 1 (SP1), Standard Edition | 4 GB | 32 GB |
Physical Memory Limits: Windows Server 2003
The following table specifies the limits on physical memory for Windows Server2003. Limits over 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit on X86 | Limit on IA64 |
|---|---|---|
| Windows Server2003, Datacenter Edition | 64 GB (16 GB with 4GT) | 512 GB |
| Windows Server2003, Enterprise Edition | 64 GB (16 GB with 4GT) | 512 GB |
| Windows Server2003, Standard Edition | 4 GB | |
| Windows Server2003, Web Edition | 2 GB | |
| Windows Small Business Server 2003 | 4 GB | |
| Windows Compute Cluster Server2003 | 32 GB | |
| Windows Storage Server2003, Enterprise Edition | 8 GB | |
| Windows Storage Server2003 | 4 GB |
Physical Memory Limits: Windows XP
The following table specifies the limits on physical memory for WindowsXP.
| Version | Limit on X86 | Limit on X64 | Limit on IA64 |
|---|---|---|---|
| WindowsXP | 4 GB | 128 GB | 128 GB (not supported) |
| WindowsXP Starter Edition | 512 MB | N/A | N/A |
Physical Memory Limits: Windows Embedded
The following table specifies the limits on physical memory for Windows Embedded.
| Version | Limit on X86 | Limit on X64 |
|---|---|---|
| Windows XP Embedded | 4 GB | |
| Windows Embedded Standard 2009 | 4 GB | |
| Windows Embedded Standard 7 | 4 GB | 192 GB |
How graphics cards and other devices affect memory limits
Devices have to map their memory below 4 GB for compatibility with non-PAE-aware Windows releases. Therefore, if the system has 4GB of RAM, some of it is either disabled or is remapped above 4GB by the BIOS. If the memory is remapped, X64 Windows can use this memory. X86 client versions of Windows don’t support physical memory above the 4GB mark, so they can’t access these remapped regions. Any X64 Windows or X86 Server release can.
X86 client versions with PAE enabled do have a usable 37-bit (128 GB) physical address space. The limit that these versions impose is the highest permitted physical RAM address, not the size of the IO space. That means PAE-aware drivers can actually use physical space above 4 GB if they want. For example, drivers could map the "lost" memory regions located above 4 GB and expose this memory as a RAM disk.
4-Gigabyte Tuning
IMAGE_FILE_LARGE_ADDRESS_AWARE
Physical Address Extension
