This topic describes memory limits for supported Windows 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.
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.
| Memory type | Limit in 32-bit Windows | 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
4 GB with IMAGE_FILE_LARGE_ADDRESS_AWARE
|
| User-mode virtual address space for each 64-bit process |
Not applicable
|
2 GB x64: 8 TB with IMAGE_FILE_LARGE_ADDRESS_AWARE
Intel IPF: 7 TB with IMAGE_FILE_LARGE_ADDRESS_AWARE
|
| Kernel-mode virtual address space |
2 GB
From 1 GB to a maximum of 2 GB with 4GT
|
8 TB
|
| Paged pool |
Limited by available kernel-mode virtual address space or the
PagedPoolLimit registry key value. Windows Vista: Limited only by kernel mode virtual address space. Starting with Windows Vista Service Pack 1 (SP1), the paged pool can also be limited by the
PagedPoolLimit registry key value.
Windows Home Server and Windows Server 2003: 530 MB
Windows XP: 490 MB
Windows 2000: 350 MB
|
128 GB Windows Server 2003 and Windows XP: Up to 128 GB depending on configuration and RAM.
Windows 2000: Not applicable
|
| Nonpaged pool |
Limited by available kernel-mode virtual address space, the
NonPagedPoolLimit registry
key value, or physical memory.
Windows Vista: Limited only by kernel mode virtual address space and physical memory. Starting with
Windows Vista SP1, the nonpaged pool can also be limited by the
NonPagedPoolLimit
registry key value.
Windows Home Server, Windows Server 2003, and Windows XP/2000: 256 MB, or 128 MB with 4GT.
|
75% of RAM up to a maximum of 128 GB Windows Vista: 40% of RAM up to a maximum of 128 GB.
Windows Server 2003 and Windows XP: Up to 128 GB depending on configuration and RAM.
Windows 2000: Not applicable
|
| 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.
Windows Vista: Limited only by kernel mode virtual address space. Starting with
Windows Vista SP1, system cache virtual address space can also be limited by the
SystemCacheLimit
registry key value.
Windows Home Server, Windows Server 2003, and Windows XP/2000: 860 MB with LargeSystemCache
registry key set and without 4GT; up to 448 MB with 4GT.
|
Always 1 TB regardless of physical RAM Windows Server 2003 and Windows XP: Up to 1 TB depending on configuration and RAM.
Windows 2000: Not applicable
|
Physical Memory Limits: Windows Server 2008
The following table specifies the limits on physical memory for Windows Server 2008. Limits greater than 4 GB
for 32-bit Windows assume that PAE is enabled.
| Version | Limit in 32-bit Windows | Limit in 64-bit Windows |
|---|
| Windows Server 2008 Datacenter (full installation) |
64 GB
|
2 TB
|
| Windows Server 2008 Datacenter (Server Core installation) |
64 GB
|
2 TB
|
| Windows Server 2008 Enterprise |
64 GB
|
2 TB
|
| Windows Server 2008 Standard |
4 GB
|
32 GB
|
| Windows Server 2008 for Itanium-Based Systems |
Not applicable
|
2 TB
|
| Windows Web Server 2008 |
4 GB
|
32 GB
|
Physical Memory Limits: Windows Vista
The following table specifies the limits on physical memory for Windows Vista.
| Version | Limit in 32-bit Windows | Limit in 64-bit Windows |
|---|
| Windows Vista Ultimate |
4 GB
|
128 GB
|
| Windows Vista Enterprise |
4 GB
|
128 GB
|
| Windows Vista Business |
4 GB
|
128 GB
|
| Windows Vista Home Premium |
4 GB
|
16 GB
|
| Windows Vista Home Basic |
4 GB
|
8 GB
|
| Windows Vista Starter |
4 GB
|
Not applicable
|
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
The following table specifies the limits on physical memory for Windows Server 2003. Limits over 4
GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit in 32-bit Windows | Limit in 64-bit Windows |
|---|
| Windows Server 2003 Service Pack 2 (SP2), Datacenter Edition |
128 GB
64 GB with 4GT
|
2 TB
|
| Windows Server 2003 Service Pack 2 (SP2), Enterprise Edition |
64 GB
|
2 TB
|
| Windows Storage Server 2003, Enterprise Edition |
8 GB
|
Not applicable
|
| Windows Storage Server 2003 |
4 GB
|
Not applicable
|
|
Windows Server 2003 R2 Datacenter Edition
Windows Server 2003 with Service Pack 1 (SP1), Datacenter Edition
|
128 GB
16 GB with 4GT
|
1 TB
|
|
Windows Server 2003 R2 Enterprise Edition
Windows Server 2003 with Service Pack 1 (SP1), Enterprise Edition
|
64 GB
16 GB with 4GT
|
1 TB
|
|
Windows Server 2003 R2 Standard Edition
Windows Server 2003, Standard Edition SP1
Windows Server 2003, Standard Edition SP2
|
4 GB
|
32 GB
|
| Windows Server 2003, Datacenter Edition |
128 GB
16 GB with 4GT
|
512 GB
|
| Windows Server 2003, Enterprise Edition |
32 GB
16 GB with 4GT
|
64 GB
|
| Windows Server 2003, Standard Edition |
4 GB
|
16 GB
|
| Windows Server 2003, Web Edition |
2 GB
|
Not applicable
|
| Windows Small Business Server 2003 |
4 GB
|
Not applicable
|
| Windows Compute Cluster Server 2003 |
Not applicable
|
32 GB
|
Physical Memory Limits: Windows XP
The following table specifies the limits on physical memory for Windows XP.
| Version | Limit in 32-bit Windows | Limit in 64-bit Windows |
|---|
| Windows XP |
4 GB
|
128 GB
|
| Windows XP Starter Edition |
512 MB
|
Not applicable
|
Physical Memory Limits: Windows 2000
The following table specifies the limits on physical memory for Windows 2000.
| Version | Limit in 32-bit Windows |
|---|
| Windows 2000 Professional |
4 GB
|
| Windows 2000 Server |
4 GB
|
| Windows 2000 Advanced Server |
8 GB
|
| Windows 2000 Datacenter Server |
32 GB
|
See Also
4-Gigabtye Tuning
IMAGE_FILE_LARGE_ADDRESS_AWARE
Physical Address Extension
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Build date: 10/2/2008