Memory Limits for Windows and Windows Server Releases

来源：https://msdn.microsoft.com/en-us/library/windows/desktop/aa366778(v=vs.85).aspx

Limits on memory and address space vary by platform, operating system, and by whether the IMAGE_FILE_LARGE_ADDRESS_AWARE value of the LOADED_IMAGEstructure 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 withIMAGE_FILE_LARGE_ADDRESS_AWAREcleared (default) 4 GB withIMAGE_FILE_LARGE_ADDRESS_AWAREset
User-mode virtual address space for each 64-bit process	Not applicable	With IMAGE_FILE_LARGE_ADDRESS_AWAREset (default): x64:  8 TB Intel Itanium-based systems:  7 TB Windows 8.1 and Windows Server 2012 R2:  128 TB 2 GB withIMAGE_FILE_LARGE_ADDRESS_AWAREcleared
Kernel-mode virtual address space	2 GB From 1 GB to a maximum of 2 GB with 4GT	8 TB Windows 8.1 and Windows Server 2012 R2:  128 TB
Paged pool	384 GB or system commit limit, whichever is smaller. Windows 8.1 and Windows Server 2012 R2:  15.5 TB or system commit limit, whichever is smaller. Windows Server 2008 R2, Windows 7, Windows Server 2008 and Windows Vista:  Limited by available kernel-mode virtual address space. Starting with Windows Vista with Service Pack 1 (SP1), the paged pool can also be limited by thePagedPoolLimit registry key value. Windows Home Server and Windows Server 2003:  530 MB Windows XP:  490 MB	384 GB or system commit limit, whichever is smaller Windows 8.1 and Windows Server 2012 R2:  15.5 TB or system commit limit, whichever is smaller. Windows Server 2008 R2, Windows 7, Windows Server 2008 and Windows Vista:  128 GB or system commit limit, whichever is smaller Windows Server 2003 and Windows XP:  Up to 128 GB depending on configuration and RAM.
Nonpaged pool	75% of RAM or 2 GB, whichever is smaller. Windows 8.1 and Windows Server 2012 R2:  RAM or 16 TB, whichever is smaller (address space is limited to 2 x RAM). 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:  256 MB, or 128 MB with 4GT.	RAM or 128 GB, whichever is smaller (address space is limited to 2 x RAM) Windows 8.1 and Windows Server 2012 R2:  RAM or 16 TB, whichever is smaller (address space is limited to 2 x RAM). Windows Server 2008 R2, Windows 7 and Windows Server 2008:  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.
System cache virtual address space (physical size limited only by physical memory)	Limited by available kernel-mode virtual address space or the SystemCacheLimitregistry key value. Windows 8.1 and Windows Server 2012 R2:  16 TB. 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 theSystemCacheLimit registry key value. Windows Home Server, Windows Server 2003 and Windows XP:  860 MB withLargeSystemCache registry key set and without 4GT; up to 448 MB with 4GT.	Always 1 TB regardless of physical RAM Windows 8.1 and Windows Server 2012 R2:  16 TB. Windows Server 2003 and Windows XP:  Up to 1 TB depending on configuration and RAM.

Physical Memory Limits: Windows 10

The following table specifies the limits on physical memory for Windows 10.

Version	Limit on X86	Limit on X64
Windows 10 Enterprise	4 GB	2TB
Windows 10 Education	4 GB	2TB
Windows 10 Pro	4 GB	2TB
Windows 10 Home	4 GB	128GB

Physical Memory Limits: Windows 8

The following table specifies the limits on physical memory for Windows 8.

Version	Limit on X86	Limit on X64
Windows 8 Enterprise	4 GB	512 GB
Windows 8 Professional	4 GB	512 GB
Windows 8	4 GB	128 GB

Physical Memory Limits: Windows 7

The following table specifies the limits on physical memory for Windows 7.

Version	Limit on X86	Limit on X64
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	N/A