How much RAM Memory can I install in my Windows computer? What does it depend on?

Your computer has a certain number of sockets for memory on its logic board. That will define how many modules can be installed. The machine will also have a maximum RAM module size that can be addressed. In most cases, the # of slots times the max RAM module size = the maximum amount of memory that can be installed. In some cases there may be restrictions that reduce that amount.

Some machines, usually notebooks, have memory soldered on to the motherboard, and are not upgradeable. Others will have some amount soldered on, and single socket for upgrading.

The motherboard memory controller and BIOS can limit the amount of RAM that can be installed. Typically, the memory controller can support individual memory modules up to a certain size only. If the hardware memory controller only supports 2 GB DIMMs, you cannot install 4 GB or 8 GB DIMMs. This comes down to the memory controller’s capability to recognize the number of memory chips and density on the module, at some point the controller cannot ‘count’ any higher. On rare occasions on older machines, a BIOS update allows a memory controller to utilize more memory.

Sometimes, the limits are based on the speed of the RAM modules – some motherboards support one amount of memory at one speed, but a lesser amount of memory if you choose to install higher speed modules.

With server and workstation machines, it becomes more complicated. One motherboard may have a limit of, for example 48 GB for Unbuffered RAM modules, but a limit of 128 GB for ECC Registered RAM modules. Note that you can never mix different types of ECC RAM at once – ECC Unbuffered, ECC Registered and ECC Load Reduced memory are mutually exclusive.

The limits on the amount of memory addressable may also depend on the CPU installed. Some motherboards can address more memory with a Xeon CPU than with a Core i-series.

Dual CPU servers and workstations typically can address twice the number of memory sockets that single CPU machines can. In the case of Dual CPU motherboards where only one CPU is installed, even though there may be 12 or more memory sockets on the board, the sockets addressed by the second CPU will be unusable. Consult with your machine’s documentation for memory population rules for servers and workstations.

There may also be limits on the number of Ranks of memory supported. Each memory module is organized into 1, 2 or 4 Ranks of memory per module. If a motherboard has a limit of 8 Ranks total it can address, you could put in 4 sticks of Dual rank memory, but only 2 sticks of Quad-ranked memory, regardless of what the other limits may be.

The operating system can also be a limitation to the amount of RAM that can be addressed. Any 32-bit operating system will be limited to 4 GB or less of memory.

Windows 7 Starter edition is limited to 2 GB total RAM,

Among 64 GB operating systems,

Windows 7 Home Basic is limited to 8 GB,
Windows 7 Home Premium is limited to 16 GB,
Windows 7 Pro is limited to 192 GB,
Windows 8 Home is limited to 128 GB
Windows 8 Pro and Enterprise are limited to 512 GB
Windows 10 Home is limited to 128 GB
Windows 10 Pro is limited to 2 TB (2000 GB)
Windows 10 Enterprise and server editions can address many TB of RAM
@Memory Limits for Windows and Windows Server Releases

The bottom line is: You need to check the specifications of your particular motherboard, OS and CPU to know what the maximum RAM is for a given machine and what type(s) of RAM it will be able to use. Contact CanadaRAM for help in identifying the best RAM for your use.

This entry was posted in Computer Questions and Answers, Memory, Q&A, Upgrading, Windows questions. Bookmark the permalink.

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