Maximum RAM on Windows 7 and Windows 8

How much RAM can you use on the Windows 7 or on the Windows 8 operating systems?

The maximum amount of RAM that the 32-bit version of Windows 7 Home Basic OS can read is 4GB. The 64-bit version of Windows 7 can read up to 192GB RAM.

The maximum limit of RAM on the 32-bit version of Windows 8 is also 4GB while the 64-bit version can handle up to 512GB of memory. 

Here are the physical memory limits for Windows 7 and Windows 8:

Version Limit on X86 Limit on X64
Windows 7 Ultimate 4 GB 192 GB
Windows 7 Enterprise 4 GB 192 GB
Windows 7 Professional 4 GB 192 GB
Windows 7 Home Premium 4 GB 16 GB
Windows 7 Home Basic 4 GB 8 GB
Windows 7 Starter 2 GB N/A
Windows 8 Enterprise 4 GB 512 GB
Windows 8 Professional 4 GB 512 GB
Windows 8 4 GB 128 GB

Please note that X86 is the 32-bit system. For more info on memory and address limits, see the Microsoft memory site. That page also explains how graphics cards and other devices affect memory limits:

Devices have to map their memory below 4 GB for compatibility with non-PAE-aware Windows releases. Therefore, if the system has 4GB of RAM, some of it is either disabled or is remapped above 4GB by the BIOS. If the memory is remapped, X64 Windows can use this memory. X86 client versions of Windows don’t support physical memory above the 4GB mark, so they can’t access these remapped regions. Any X64 Windows or X86 Server release can.

X86 client versions with PAE enabled do have a usable 37-bit (128 GB) physical address space. The limit that these versions impose is the highest permitted physical RAM address, not the size of the IO space. That means PAE-aware drivers can actually use physical space above 4 GB if they want. For example, drivers could map the “lost” memory regions located above 4 GB and expose this memory as a RAM disk.

Before you buy more RAM

We feel that we have to bring this to your attention because since the RAM price increase announced last week a number a people have grabbed the opportunity to purchase extra RAM at the old low price of the modules we still have in stock only to find that they need to upgrade their operating system to benefit from RAM upgrades. (See our article on “How to make your computer faster.”)

Windows 8So what should you do?!

You’ll note from the online operating system store that upgrading from a 32-bit Windows 7 version to a 64-bit Windows 7 OS actually will cost you more than upgrading to a 64-bit Windows 8 OS because the new 64-bit Windows 8 Single Language version costs only R999.

Gamers and heavy computer users have necessarily been running 64-bit systems but if you’re a home user or plan to play the latest games or do some advanced picture or video editing, our advice is to go for the new 64-bit Windows 8. As we have mentioned at the launch, Windows 8 boots faster and is more modern.

Date: 29 Jan 2013