I Forgot How Much Memory...

There's a lot of confusion about what how much memory different versions of Windows can address. Some of you have paid for and installed memory that does you absolutely no good whatsoever. Here's a list of the most current Windows versions and how much memory can be used:

Windows Vista (32 bit)
Ultimate, Enterprise, Business, Home Premium, Home Basic: 4 GB
Starter: 1 GB

Windows XP (32 bit)
Professional, Home: 4GB
Starter Edition: 512 MB

Windows Server 2003 (32 bit)
Datacenter SP2: 128 GB
Enterprise SP2: 64 GB
Standard SP1: 4 GB*
Datacenter R2: 128 GB
Enterprise R2: 64 GB
Standard R2: 4 GB*
Web Edition: 4 GB*
Small Business Edition: 4 GB

* Certain Microsoft server operating systems can support over 4GB of memory via Physical Address Extension (PAE). Please refer to Microsoft knowledgebase article located here for more information.

Windows Server 2008 (32 bit)
Datacenter, Enterprise: 64 GB
Standard, Web Server: 4 GB

Windows Vista (64 bit)
Ultimate, Enterprise, Business: 128 GB
Home Basic: 8 GB

Windows XP (64 bit)
Professional: 128 GB

Windows Server 2003 (64 bit)
Datacenter SP2, Enterprise SP2: 2 TB
Standard SP1: 32 GB
Datacenter R2, Enterprise R2: 1 TB
Standard R2: 32 GB
Small Business Edition: 128 GB


Windows Server 2008 (64 bit)
Datacenter, Enterprise: 2 TB
Standard, Web Server: 32 GB