What is the maximum amount of RAM the Windows operating system can handle?

That depends on two factors: the amount of memory your computer hardware can handle, and the amount of memory your Microsoft® Windows® operating system (OS) can handle.

First, your computer hardware (motherboard) is designed to hold a maximum amount of RAM. When you look up your computer in the Crucial Memory Advisor™ tool or scan your system with the Crucial System Scanner, you will see the system maximum listed on the page that shows the compatible upgrades for your system.

Second, the OS maximum is the maximum amount of memory that your particular version of Windows, Linux, or Mac® OS can handle.

When purchasing your memory upgrade, make sure that you do not exceed the lower of the two maximums (OS and computer maximums.) Too much RAM can lower your system's performance or cause other problems. (In most cases, the system maximum is lower than the OS maximum.)


Windows 7 (32 Bit)


Starter: 2GB

All other Versions: 4GB


Windows 7 (64 Bit)


Home Basic: 8GB

Home Premium: 16GB

Professional: 192GB

Enterprise: 192GB

Ultimate: 192GB


Windows Vista (32 bit)


Ultimate: 4 GB

Enterprise: 4 GB

Business: 4 GB

Home Premium: 4 GB

Home Basic: 4 GB

Starter: 1 GB


Windows XP (32 bit)


Professional: 4 GB

Home: 4 GB

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*v
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: 64 GB

Enterprise: 64 GB

Standard: 4 GB

Web Server: 4 GB


Windows Vista (64 bit)


Ultimate: 128 GB

Enterprise: 128 GB

Business: 128 GB

Home Premium: 16 GB

Home Basic: 8 GB


Windows XP (64 bit)


Professional: 128 GB


Windows Server 2003 (64 bit)


Datacenter SP2: 2 TB

Enterprise SP2: 2 TB

Standard SP1: 32 GB

Datacenter R2: 1 TB

Enterprise R2: 1 TB

Standard R2: 32 GB

Small Business Edition: 128 GB


Windows Server 2008 (64 bit)


Datacenter: 2 TB

Enterprise: 2 TB

Standard: 32 GB

Web Server: 32 GB


Here are the OS maximums for some older versions of Microsoft Windows:


  • Windows 95: 1GB

  • Windows 98: 1GB

  • Windows 98SE: 1GB

  • Windows ME: 1.5GB

  • Windows NT: 4GB

  • Windows 2000 Professional: 4GB

  • Windows 2000 Server: 4GB

  • Windows 2000 Advanced Server: 8GB with PAE enabled

  • Windows 2000 Datacenter Server: 32GB with PAE enabled



Here are the maximums for some other platforms:


  • OS X (including v. 10.6 "Snow Leopard"): 64GB due to current hardware limitations (the current maximum memory capacity of Apple's highest-end system, the Mac Pro 12-Core)

  • OS 9.x: 1.5GB (no single application can utilize more than 1GB)

  • Red Hat Linux 2.4 kernel: 64GB



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