The following table specifies the limits on physical memory for Windows Server 2003. Limits greater than 4 GB for 32-bit Windows assume that PAE is enabled.
| Version | Limit in 32-bit Windows | Limit in 64-bit Windows |
| Windows Server 2003 with Service Pack 2 (SP2), Datacenter Edition | 128 GB | IA64 2 TB |
| 64 GB with 4GT | X64 1 TB | |
| Windows Server 2003 with Service Pack 2 (SP2), Enterprise Edition | 64 GB | IA64 2 TB |
| X64 1 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 | 128 GB | 1 TB |
| Windows Server 2003 with Service Pack 1 (SP1), Datacenter Edition | 16 GB with 4GT | |
| Windows Server 2003 R2 Enterprise Edition | 64 GB | 1 TB |
| Windows Server 2003 with Service Pack 1 (SP1), Enterprise Edition | 16 GB with 4GT | |
| Windows Server 2003 R2 Standard Edition | 4 GB | 32 GB |
| Windows Server 2003, Standard Edition SP1 | ||
| Windows Server 2003, Standard Edition SP2 | ||
| Windows Server 2003, Datacenter Edition | 128 GB | 512 GB |
| 16 GB with 4GT | ||
| Windows Server 2003, Enterprise Edition | 32 GB | 64 GB |
| 16 GB with 4GT | ||
| 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 |
***Windows Server 2008 R2 is available only in 64-bit editions.
