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What happens when you install > 4GB of RAM in a computer with a 32-Bit OS?

I have 32 bit windows 7 operating System with 2GB RAM. One IDES Software has been installed in the system. But it runs very slowly. I have been told to increase the RAM to 6GB. But I have read that a 32bit operating system can use a maximum of 4GB RAM. I would like to know if this is true? If yes, how? What installing an extra 4 GB RAM improve the performance or do I have to change the OS to a 64 bit one?

Community
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Ashwin
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  • Who told you to increase the system memory to 6GB because its sounds like that person knows less then you do. A 32-bit operating system will not use more then 4GB, even if it it, increasing the amount of memory has never really made a computer faster. – Ramhound Sep 05 '12 at 12:31

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You are correct. Unless you use a 64bit OS, the 32bit OS will not see more than 4GB Physical Memory Limits: Windows 7

The following table specifies the limits on physical memory for Windows 7.

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

Source

However (and I appreciate this is probably not applicable to you, I include only for completeness), please note you can of course run 32-bit software on a 64-bit OS. The only way you'll get the full benefit is to run 64-bit software on a 64bit OS.

Dave
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  • I have windows 7 Ultimate 32 bit. How can I know whether PAE is present in it or not? – Ashwin Sep 05 '12 at 13:01
  • It isn't. Not since XP service pack 2. The reason was that most drivers weren't PAE aware and threw their toys out of their pram if they ended up in memory above the 4 GB boundary. More details: http://superuser.com/questions/52275/how-can-i-enable-pae-on-windows-7-32-bit-to-support-more-than-3-5-gb-of-ram – Dave Sep 05 '12 at 13:03
  • What would be the result if it is a 32 bit processor but a 64 bit OS? – Ashwin Sep 05 '12 at 17:50
  • The software only utilises the 32 bit architecture and therefore only uses up to 4gb. However, depending on the code it is possible it won't run but unlikely. – Dave Sep 06 '12 at 05:48
  • One last question. How can I know If I have a 32 bit processor or a 64 bit one? – Ashwin Sep 06 '12 at 07:27
  • Click start, right click on My Computer and select properties. It will give you information about your processor - from here, you can search for the model in a search engine. – Dave Sep 06 '12 at 07:35
  • I have though of installing windows 64 bit and 6GB RAM. But before doing that, I just added a 4GB RAM to the system without changing the OS. SO now I have totally 6GB RAM and 32 bit OS. But my system properties reads " Installed Memory (RAM) : 6GB (2.92GB usable). Why is it using only 3GB instead of 4GB? – Ashwin Sep 07 '12 at 03:31
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    This has been asked before so pleae search for a detailed answer but quickly, it is because the OS reserves X amount of memory. And it does vary between computers. – Dave Sep 07 '12 at 05:40
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Per the TechNet article Memory Limits for Windows Releases, 32-bit versions of Windows 7 can support a maximum of 4GB of RAM. In my experience, even when I put 4GB of RAM in a 32-bit Windows 7 system, it only recognizes a portion of the memory (~3.6GB)

bobmagoo
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It depends largely on the OS. Most 'consumer' versions of Windows will be limited to 4GB on their 32-bit versions however the server versions have full PAE support (allowing up to 64GB)

Most Linux distributions will also allow use of higher amounts of RAM via PAE.

PhonicUK
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  • I don't know if this is the case - I think all (other than starter and possibly basic) W7 disc come with both 32bit and 64 bit discs. – Dave Sep 05 '12 at 11:36
  • Only when bought retail. If you've got an OEM installation then you may only have access to whatever version was originally installed. – PhonicUK Sep 05 '12 at 11:59
  • Ah, sorry. I now understand. Thank you for clarification. – Dave Sep 05 '12 at 11:59
  • @PhonicUK - You are mistaken. All Windows 7 licenses(except Starter and Basic) can be upgraded to a 64-bit installation. It is only Windows Server 2008 R2 that has specific licenses in that regard. Furthermore Windows 7 Starter and Windows 7 Basic cannot be "purchase" by a customer they are only found on specific devices meeting very specific guidelines. The right to upgrade to a 64-bit installation extends to an OEM license also. – Ramhound Sep 05 '12 at 12:34
  • @Ramhound The licence is indeed non specific (And 2008 R2 has no 32 bit version at all), but they'd still need access to the installation media of course which they may not have with an OEM install (or rather, the OEM media may only have the version that was preinstalled) – PhonicUK Sep 05 '12 at 12:36
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    +1, even though it might not be the best answer, I learned a new thing today: PAE. :D –  Sep 05 '12 at 12:45
  • @Ramhound Basic can be too. An image in the `install.wim` exists, there are just no official discs for it. – kinokijuf Jan 10 '14 at 05:34