32 bit OS and 64 bit OS RAM Capacity

    General discussion

  • Hi,

    I currently have the 32 bit edition of Windows 7 Beta for both my laptop and my desktop. It works great! And, most importantly, it works well with all my programs that may not function properly on a 64 bit OS. However, I want to upgrade the RAM on my desktop to more than3.5 GB of RAM. On Windows XP 32 bit this wasn't possible because, to my understanding, of the way Windows XP was put together. Online I can't find any reason that Windows 7 shouldn't be able to handle more than 3.5 GB of RAM.

    So my question is why is there a restriction placed to inconvience those who want to continue using the 32 bit OS?

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    Saturday, September 12, 2009 12:16 AM

All replies

  • It's my understanding that the 4g limit on RAM is a mathematical limitation, not a limitation set by a particular OS. It has more to do with 32 bit than with being a Windows PC. Which MB's and Processors are you running on? This too may limit the amount of RAM you can install if either piece of hardware are limited to 32 bit operation. There are those here who can explain it better than I can. You can BTW run some 32 bit applications on the Win7 64x platform. I am doing so now without any problems so far. Drivers are a bigger problem, but I've had to work to put older hardware in this test beast that Win7s driver catolog hasn't picked up on automatically.

    Saturday, September 12, 2009 1:04 AM
  • It's like they said. But it's a very complex topic.   You see it's possible to enable a 32-bit OS to have more ram than 4GB.  Windows Server 2000 and 2003 Database editions (Both 32-bit) can have up to 64 GB ram installed.    However it can't be confused with the 32-bit limitation which is 4GB.    Because a 32-bit os can only access 4GB of memory. 

    I am lazy so read this :

    But true 64-bit can access 16 Exabytes or EB (1EB =1000TB or 1024 for ya binary freaks).  Windows 7 64-bit limitation for Ultimate and Business Editions is 128GB.   Most current Mother Boards and computers have a hardware limit of 8 or 16GB though I would not be surprised if a 32GB motherboard is out or on its way out by now.  

    bottom line:  With PAE. current 32-bit processors and OS can install more than 4GB of ram but it's only suitable for a database server and not for consumer/end user level product.  x64 or true 64-bit is a better and more robust method which is what you want in a consumer/end user product. 
    Saturday, September 12, 2009 6:26 AM
  • Just as a casual note, some laptop manuals state that their motherboards/BIOS support (up to) 4GB, when they readily support up to 8GB. Maybe this was due to the 4GB not being available in a SODIMM package at the time the notebook was being produced, but I can testify that at least mine works with 8GB RAM. I have been told that there are cases in which  laptops sold with an AMD 64-bit CPU, a 32-bit version of VISTA and 3 to 4GB of RAM have successfully been upgraded to 8GB RAM, and I feel sure that there are those with Intel CPUs that work the same way. ...not sure about whether or not there might be a limiting factor in regard to the  memory controller, but if it is integrated with a 64-bit CPU, it should offer no problem...
    Saturday, September 12, 2009 6:36 AM
  • My Dell Inspiron 1520 sees 3.838 GB.  Close enough for me, XP or 7.  No conspiracy or failing here.

    Sunday, September 13, 2009 2:47 AM
  • As others said, It's not an artificial limitation imposed by MS.  And, it had nothing to do with "the way that XP was put together" (at least, nothing more than that it was 32-bit.)  Rather, it's an architectural limitation of a 32-bit OS.
    I did a write-up on this (over at the MaximumPC forums) to answer the bazillion questions that came up on this topic:


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    Sunday, September 13, 2009 3:39 AM
  • Roughly: 1EB = 1,000PB = 1,000,000TB


    Also: "In principle, the 64-bit microprocessors found in many computers can address 16 exbibytes, or just over 18 exabytes, of memory."



    Wednesday, July 07, 2010 4:49 PM