Thinking of a memory upgrade? An operating system upgrade? Here’s a table from msdn stating the limits imposed by 32 and 64 bit editions of various Windows versions.
Physical Memory Limits: Windows 7
The following table specifies the limits on physical memory for Windows 7.
| Version | Limit in 32-bit Windows | Limit 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 |
| Version | Limit in 32-bit Windows | Limit in 64-bit Windows |
|---|
| Windows XP | 4 GB | 128 GB |
| Windows XP Starter Edition | 512 MB | Not applicable |
| Version | Limit 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 |