What is the RAM Limit in Windows 10?

This post has not been updated since the official Windows 10 release. However the information is accurate.
WARNING: These limits do not take in account the RAM limits of hardware!


Windows 10. 4GB


Windows 10. 128 GB

Windows 10 Professional. 512 GB

Windows 10 Enterprise. 512 GB


Why is 4GB the Limit for 32-bits Architectures?

Simply explained. RAM contains of bytes. And each of these bytes needs it own address, and there’s were the problems are coming. The 32 bits processors can only use addresses that are 32 bits long.

Each memory address can have 2 values. 1 and 0. So 2^32 + 1 (0 is valid) so with the math done that comes down at 4,294,967,296 bits.

Let’s calculate that further.

4,294,967,296 bits is 4194304 kilobytes (devided by 1024)

4194304 kilobytes is 4096 megabytes (devided by 1024)

4096 megabytes is 4 gigabytes (devided by 1024).

Hence the 4 gigabytes limit, there is just no space left. For normal processors (NON PAE-Extended)  to leave the information.

What is the theoratical limit for 64-bits Architectures then?

The same calculation as I explained above can be applied.

Each memory address can have 2 values. 1 and 0. So 2^64 + 1 (0 is valid) so with the math done that comes down at 18446744073709551616 bits. (Damn thats a huge number: eighteen quintillion, four hundred forty-six quadrillion, seven hundred forty-four trillion, seventy-three billion, seven hundred nine million, five hundred fifty-one thousand, six hundred sixteen)

Let’s do some math again shall we?

18446744073709551616 bits is 18014398509481984 kilobytes (devided by 1024)

18014398509481984 kilobytes is 2199023255552 megabytes

2199023255552 megabytes is 2147483648 gigabytes

2147483648 gigabytes is 2097152 terabytes

2097152 terabytes is 2048 petabytes.

Alright let’s just stop there shall we? A picture might explain it better.

8GB Ram Stick What is the RAM Limit in Windows 10? ram limit in windows 10

8GB Ram Stick

See the above image? You need 268435456 (two hundred sixty-eight million, four hundred thirty-five thousand, four hundred fifty-six) of those to reach the 64 bits limit.



Although very careful calculations I might have made a typo somewhere, please do comment where needed.

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About The Author
Yuri Pustjens
Yuri Pustjens
2014, 2015 & 2016 Microsoft Most Valuable Professional Windows Yuri specializes in troubleshooting (crash analysis and devices), system resource utilisation and system performance. He is also very interested in Customer Security. Yuri can be found as Windows Community Moderator and Wiki Author on Microsoft Answers and is active on different communities all across the web.
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