Windows 7: regarding RAM for 32 bit Operating Systems

The 32-bit editions of Windows Vista are limited to 4GB not because of any physical or technical constraint on 32-bit operating systems. The 32-bit editions of Windows Vista all contain code for using physical memory above 4GB. Microsoft just doesn’t license you to use that code. Meaning that you can infact, use more than 4GB of RAM on a 32 bit OS.
The 4GB limit is retrieved from the registry by calling a function named ZwQueryLicenseValue. I'm wondering why Microsoft has decided to put a 4GB restriction on 32 bit processors?

Hi and welcome to SF. I think you might like to investigate this further. Failing that why dont you take a prtscreen of the value and upload it so we can all see it. I just did a search thru my win 7 registry and its not there. just google the 32 bit ram limit and i think you will find a different answer

Again welcome to SF

Ken

The main reason 32-bit was limited to no more then 4gb RAM was due to the fact that if the 32-bit OS attempted to use more it would in almost every case become unstable and crash.

If you remove the check for the licensed memory limit then a restriction to 4GB is demonstrably not enforced by other means. Yet I must admit that I have not found where Microsoft says directly that 32-bit Windows Vista is limited to 4GB only by licensing. The supposed License Agreement doesn’t even mention the word memory. What is going on?

So you are saying in this post that MS prevents you to use more RAM in 32-bit Windows correct?

I assume you are not talking abt windows server editions with their memory management system just plain vanilla client side windows. Right?

Ken

Yes that is what I am trying to explain. A surprising number of people who claim some sort of attention as expert commentators would have you believe that using more than 4GB is mathematically impossible for any 32-bit operating system because 2 to the power of 32 is 4G. If nothing else, they don’t know enough history: 2 to the 16 is only 64K and yet the wealth of Microsoft is founded on a 16-bit operating system that from its very first version was designed to use 640KB of RAM plus other memory in a physical address space of 1MB. It's not that the 32 bit cannot handle more than 4 GB of RAM, nor is it unstable. The extra RAM (beyond 4 GB) is, quit simply, ignored. Vista will pick up that you have 8 GB of RAM for instance but it will not be used whatsoever, and yes I have tested this on Vista Ultimate in safe mode. But my question remains unanswered. Why is Microsoft limiting us to 4 GB with the 32 bit OS? Could this be some sort of marketing scheme? I don't think so but I would very much like a response.

So that would mean every x86 distro of Linux is limiting us as well then right? Seeing as both Windows and Linux x86 have a 4gb limit.

The means for a 32-bit operating system to use physical addresses above 4GB was built into Intel’s 32-bit processors well over a decade ago and has been supported by Microsoft since Windows 2000. If you haven’t heard of it, or haven’t thought that it applies to Windows Vista, then one reason may be that Microsoft advertises it only as a feature of the server editions such as Windows 2000 Server and Windows Server 2003, and only then for the more expensive levels with names like Enterprise and Datacenter. However, even Windows 2000 Professional can be configured, without contrivance, to access memory above 4GB by using Physical Address Extension (PAE). This is old technology. It’s also widely and deeply misunderstood technology, arguably more than any other in the history of personal computing.

The total amount of memory allowed is taken solely from the license value Kernel-WindowsMaxMemAllowedx86, as read through the undocumented function ZwQueryLicenseValue. The data for this value is a number of MB, so that 0x1000, which is installed for all 32-bit editions of Windows Vista, means 4GB.