What is the maximum memory (RAM) limit for 64-bit Windows 7/8 ?

Different Windows editions have had different upper maximum RAM limits. 64-bit Windows support different amounts of memory as a SKU differentiating feature, with the low end being 512MB for Windows XP Starter to 128GB for Vista Ultimate and 192GB for Windows 7 Ultimate.

All 32-bit Windows client SKUs, however, including Windows Vista, Windows XP and Windows 2000 Professional, support a maximum of 4GB of physical memory. 4GB is the highest physical address accessible with the standard x86 memory management mode. Hardware Specifications for Windows 7 lays down the minimum memory (RAM) requirements.

Read: Difference between 64-bit and 32-bit Windows.

Maximum memory (RAM) limits

So, while the maximum RAM limit for 32-bit Windows 7 / 8 editions is 4GB, when it comes to the 64-bit editions, the amount of memory that the OS can address depends on which edition you are running.

Here are the upper RAM limits for the different editions of Windows 7 64-bit:

  • Starter : 2GB
  • Home Basic : 8GB
  • Home Premium : 16GB
  • Professional: 192GB
  • Enterprise : 192GB
  • Ultimate : 192GB

These limits are similar to those for Windows Vista editions, except that Vista Enterprise and Vista Ultimate have had their upper limits raised from 128GB to 192GB.

Windows 8 and Windows 8.1, 64-bit has different memory limits depending on the edition.

  • Windows 8: 128GB
  • Windows 8 Professional: 512GB
  • Windows 8 Enterprise: 512GB.

For Windows Server 2008 R2 Enterprise edition, the limit could extend to even 2 TB.

Hope this helps.

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Anand Khanse is the Admin of TheWindowsClub.com, a 10-year Microsoft MVP Awardee in Windows (2006-16) & a Windows Insider MVP. Please read the entire post & the comments first, create a System Restore Point before making any changes to your system & be careful about any 3rd-party offers while installing freeware.