Memory Limits for Windows Operating System Related

Physical Memory Limits: 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	2 GB

Physical Memory Limits: Windows Server 2008 R2

Version	Limit on X64	Limit on IA64
Windows Server 2008 R2 Datacenter	2 GB
Windows Server 2008 R2 Enterprise	2 GB
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

Version	Limit on X86	Limit on X64
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 Small Business Server 2008	4 GB	32 GB
Windows Web Server 2008 R2	4 GB	32 GB

Physical Memory Limits: Windows Vista

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

Physical Memory Limits: Windows Server 2003 R2

Version	Limit on X86	Limit on X64
Windows Server 2003 R2 Datacenter Edition	64 GB	1 TB
Windows Server 2003 R2 Enterprise Edition	64 GB	1 TB
Windows Server 2003 R2 Standard Edition	4 GB	32 GB

Physical Memory Limits: Windows Server 2003 SP1

Version	Limit on X86	Limit on X64
Windows Server 2003 (SP1), Datacenter Edition	64 GB	1 TB
Windows Server 2003 (SP1), Enterprise Edition	64 GB	1 TB
Windows Server 2003 (SP1), Standard Edition	4 GB	32 GB

Physical Memory Limits: Windows Server 2003 SP2

Version	Limit on X86	Limit on X64
Windows Server 2003 (SP2), Datacenter Edition	64 GB	1 TB
Windows Server 2003 (SP2), Enterprise Edition	64 GB	1 TB
Windows Server 2003 (SP2), Standard Edition	4 GB	32 GB

Physical Memory Limits: Windows Server 2003

Version	Limit on X86	Limit on X64
Windows Server 2003, Datacenter Edition	64 GB	512 GB
Windows Server 2003, Enterprise Edition	64 GB	512 GB
Windows Server 2003, Standard Edition	4 GB
Windows Server 2003, Web Edition	2 GB
Windows Small Business Server 2003	4 GB
Windows Compute Cluster Server 2003		32 GB
Windows Storage Server 2003, Enterprise Edition	8 GB
Windows Storage Server 2003	4 GB