What is the real virtual memory of the operating system? (2: Memory limit in Windows)

Before proceeding with this note, we will first list the maximum limits of physical memory supported by various Windows releases:

1. Memory and address space restrictions

Memory type	Limit in on x86	Limit in 64-bit windows
Virtual Address Space of 32-bit process user State	2 GB Up to 3 GBImage_file_large_address_awareAnd 4gt	2 GBImage_file_large_address_awareCleared (default) 4 GBImage_file_large_address_awareSet
The virtual address in the 64-bit user mode is empty.	N/	With image_file_large_address_awareSet (default ): X64:8 TB Intel itanium-based systems:7 TB 2 GBImage_file_large_address_awareCleared
Core-state virtual address space	2 GB From 1 GB to a maximum of 2 GB with 4gt	8 TB
Page pool	Limited by available kernel-mode virtual address space or the pagedpoollimit registry key value. 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 the pagedpoollimit registry key value. For Windows home server and Windows Server 2003:530 MB Windows XP:490 MB	128 GB Windows Server 2003 and Windows XP:Up to 128 GB depending on configuration and ram.
Non-page 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: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.
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: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.

2. Physical memory restrictions

Windows 8 2.1

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

2.2 Windows Server 2012

Version	Limit on x64
Windows Server 2012 datacenter	4 TB
Windows Server 2012 Standard	4 TB
Windows Server 2012 Essentials	64 GB
Windows Server 2012 Foundation	32 GB
Windows Storage Server 2012 workgroup	32 GB
Windows Storage Server 2012 Standard	4 TB
Hyper-V server 2012	4 TB

2.3 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/

2.4 Windows Server 2008 r2

Version	Limit on x64	Limit on IA64
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

2.5 Windows Server 2008

Version	Limit on x86	Limit on x64	Limit on IA64
Windows Server 2008 datacenter	64 GB	1 Tb
Windows Server 2008 Enterprise	64 GB	1 Tb
Windows Server 2008 HPC Edition		128 GB
Windows Server 2008 Standard	4 GB	32 GB
Windows Server 2008 for itanium-based systems			2 TB
Windows sm-all Business Server 2008	4 GB	32 GB
Windows Website Server 2008	4 GB	32 GB

Windows Vista 2.6

Version	Limit on x86	Limit on x64
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

2.7 windows home server

Windows home server is only 32-bit, with a maximum physical memory of 4 GB.

2.8 Windows Server 2003 r2

Version	Limit on x86	Limit on x64
Windows Server 2003 r2 datacenter Edition	64 GB (16 GB with 4gt)	1 Tb
Windows Server 2003 R2 Enterprise Edition	64 GB (16 GB with 4gt)	1 Tb
Windows Server 2003 R2 Standard Edition	4 GB	32 GB

2.9 Windows Server 2003 with Service Pack 2 (SP2)

Version	Limit on x86	Limit on x64	Limit on IA64
Windows Server 2003 with Service Pack 2 (SP2), datacenter Edition	64 GB (16 GB with 4gt)	1 Tb	2 TB
Windows Server 2003 with Service Pack 2 (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

2.10 Windows Server 2003 with Service Pack 1 (SP1)

Version	Limit on x86	Limit on x64	Limit on IA64
Windows Server 2003 with Service Pack 1 (SP1), datacenter Edition	64 GB (16 GB with 4gt)	X64 1 Tb	1 Tb
Windows Server 2003 with Service Pack 1 (SP1), Enterprise Edition	64 GB (16 GB with 4gt)	X64 1 Tb	1 Tb
Windows Server 2003 with Service Pack 1 (SP1), Standard Edition	4 GB	32 GB

2.11 Windows Server 2003

Version	Limit on x86	Limit on IA64
Windows Server 2003, datacenter Edition	64 GB (16 GB with 4gt)	512 GB
Windows Server 2003, Enterprise Edition	64 GB (16 GB with 4gt)	512 GB
Windows Server 2003, Standard Edition	4 GB
Windows Server 2003, web edition	2 GB
Windows sm-all Business Server 2003	4 GB
For Windows compute Cluster Server 2003		32 GB
Windows Storage Server 2003, Enterprise Edition	8 GB
Windows Storage Server 2003	4 GB

2.12 Windows XP

Ersion	Limit on x86	Limit on x64	Limit on IA64
Windows XP	4 GB	128 GB	128 GB (not supported)
Windows XP Starter Edition	512 MB	N/	N/

2.13 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