Memory Limits for Windows Releases



Memory Limits for Windows Releases

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. IMAGE_FILE_LARGE_ADDRESS_AWARE is set or cleared by using the /LARGEADDRESSAWARE linker option.
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 typeLimit in 32-bit WindowsLimit 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 IPF:  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
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 with 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 with 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 with 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 7

The following table specifies the limits on physical memory for Windows 7.
VersionLimit in 32-bit WindowsLimit in 64-bit Windows
Windows 7 Ultimate 4 GB
192 GB
Windows 7 Enterprise 4 GB
192 GB
Windows 7 Professional 4 GB
192 GB
Windows 7 Home Premium 4 GB
16 GB
Windows 7 Home Basic 4 GB
8 GB
Windows 7 Starter 2 GB
2 GB

Physical Memory Limits: Windows Server 2008 R2

The following table specifies the limits on physical memory for Windows Server 2008 R2. Windows Server 2008 R2 is available only in 64-bit editions.
VersionLimit in 64-bit Windows
Windows Server 2008 R2 Datacenter 2 TB
Windows Server 2008 R2 Enterprise 2 TB
Windows Server 2008 R2 for Itanium-Based Systems 2 TB
Windows Server 2008 R2 Foundation 8 GB
Windows Server 2008 R2 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 Server 2008. Limits greater than 4 GB for 32-bit Windows assume that PAE is enabled.
VersionLimit in 32-bit WindowsLimit in 64-bit Windows
Windows Server 2008 Datacenter 64 GB
2 TB
Windows Server 2008 Enterprise 64 GB
2 TB
Windows Server 2008 HPC Edition Not applicable
128 GB
Windows Server 2008 Standard 4 GB
32 GB
Windows Server 2008 for Itanium-Based Systems Not applicable
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 Windows Vista.
VersionLimit in 32-bit WindowsLimit 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 1 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.
VersionLimit in 32-bit WindowsLimit in 64-bit Windows
Windows Server 2003 with Service Pack 2 (SP2), Datacenter Edition
128 GB
64 GB with 4GT
2 TB
Windows Server 2003 with 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.
VersionLimit in 32-bit WindowsLimit 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.
VersionLimit 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

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