32-bit Vista does not support 4G memory and some mistaken transfer solutions.

By reading msdn, you can use PAE to access more physical memory. However, for a specific 32-bit process, the addressing space is still 4 GB. During the process execution, I don't know how to map this 4G memory

Where is the physical memory? The cpu mmu is responsible for ing the 4G process address space to the physical memory area with the PAE extended addressing, but through awe on Windows or MMAP in Linux, process availability

Use the physical memory that exceeds the address space of the process.
Refer:
[Awe]
Http://en.wikipedia.org/wiki/Address_Windowing_Extensions
Http://msdn.microsoft.com/en-us/library/aa366527.aspx

[PAE]
Http://en.wikipedia.org/wiki/Physical_Address_Extension
Http://msdn.microsoft.com/en-us/library/aa366796.aspx

 

Another article on the Internet:

Windows Vista is a resource-consuming operating system, especially memory. In a sense, to improve the system performance of running Windows Vista, the simplest and most effective way is to expand the system

Add as much memory as possible. How much physical memory does Windows Vista support?

According to the specifications provided by Microsoft, except that starter only supports 1 GB of memory, other versions of Windows Vista (32-bit) can support 4 GB of "Memory"-of course, 32-bit x86 system, 64-bit windows

There is no corresponding starter version for Vista x64-however, it should be noted that the so-called "4 GB" here is not equivalent to the real physical memory, but the available memory addressing space.

I believe that users with a computer base know that for 32-bit systems, 4 GB is the limit of their addressable space, unless PAE (physical address extension: physical address extension) will

Memory is expanded as pages in 4 GB space by ing. In this 4 GB address space, you must leave a location for the computer's system resources such as bios, graphics card, PCI-Express, and other PCI interfaces.

Let's take a simple look at the 4 GB addressing space supported by Windows Vista x86: first, the BIOS should occupy at least kb. Of course, this is a small number. Second, the video card must be slightly larger

For example, if you want to use aero glass at a high resolution, MB of memory is required, this also means that the MB view of the video card must be in the 4 GB addressing space.

Frequency Ram is reserved. Third, for x86-based computer systems, it must retain a considerable amount of addressing space for other PCI devices, such as various Io devices. In this way, Windows Vista is addressing

Before the physical memory, the system has occupied 3.4 MB to 1 GB of addressing space by various resources. That is to say, the physical memory actually available for Windows Vista is roughly 3 GB to GB.

For a system such as Windows Vista that jumps with 1 gb ram, the system memory expandable space is too small, especially compared with Windows XP mb-4gb memory in the past. Besides, although

However, Windows Vista x86 should support PAE in the kernel, but it seems that Microsoft has no corresponding plan. Maybe Windows Vista will introduce PAE in the service pack mode in the future.

? -- Of course, it also requires the cooperation of hardware vendors, especially the CPU, chipset, and motherboard vendors.

On the other hand, although the 64-bit desktop technology, which has been widely used for several years, does not bring too many real benefits to end users, the negative impact is huge: that is, software developers are getting increasingly accustomed to "luxury" usage.

Memory resources. In the past, the "exquisite" design that achieves as many functions as possible with a small amount of memory became increasingly rare. In other words, the memory is always at least not the focus of software developers, which leads to frequent demands.

Programs that run with hundreds of megabytes or even over GB of memory. In a 32-bit Windows system, not just Windows Vista, the supported 4 GB addressing space is divided into two parts: 2 GB can be applied.

The program is used, while the other 2 GB is occupied by the system kernel. Therefore, even for Windows Vista with 4 GB of memory installed on the system, the memory available for applications is limited to 2 GB.

In some cases, the memory is insufficient. In this regard, although Microsoft's 4 Gt Ram tuning can be used to move the starting position of the kernel memory to 3 GB-to add"

The/3 GB switch is implemented to reduce the virtual address space allocated to the kernel to 1 GB, expand the address space available for the application to 3 GB-but there is still a distance from the ideal level.

Of course, the problem is even more complicated when the system hardware supports 64-bit. Windows Vista x64 supports 8 GB of memory (Windows Vista Home Basic) to 128 GB (Windows Vista Ultimate ), class

Similar addressing restrictions no longer exist.

First of all, I will only discuss about Vista 32bit. The reason is not to mention: A lot of *** hardware may not be found even with 64bit drivers.

Vista flagship version (activated), 2g memory is really limited, the kernel basically occupies 1g (Just boot 800 m, but run for a while to get to 1G ), the remaining several hundred MB is not enough, so I plan to upgrade to 4 GB.

Because I also heard that the 32-bit operating system does not fully support 4G, so I spent a lot of time reading a lot of information and finally figured out the problem ......

1. In all 32-bit windows, only win2003 SP2 (which must be SP2) can support 4G memory, but it is not perfect. Why? Because it is implemented through the PAE mode, this mode can be used to achieve a larger

Memory, but the utilization efficiency is lower than that of 64-bit windows!

2. A lot of online saying is that you can add the startup parameter bcdedit/set PAE forceenable to access 4G memory. But what is the actual situation? In fact, either theory or practice does not support this

Many people have tried it and it does not work at all, but it still shows 3G ~ 3.5 GB (the number of PCI hardware installed by the system varies, and the more devices, the less displayed). Why? The original document of msdn is referenced below

:( Http://msdn2.microsoft.com/en-us/library/aa906211.aspx)

Windows automatically enables PAE when the computer is configured for hot-add memory devices in memory ranges beyond the 4 GB region,

Defined by the static resource affinity table (srat). Hot-add memory supports memory devices that you can add without rebooting or turning

Off the computer. In this case, because PAE must be enabled when the system starts, it is enabled automatically so that the system can

Immediately address extended memory that is added between restarts. Hot-add memory is supported only on Windows Server 2008, Enterprise

Edition, Windows Server 2003, Enterprise Edition and Windows Server 2003, datacenter edition, and only on computers with an acpi bios,

X86-based processor, and specialized hardware.

That is to say, PAE can implement 32-bit windows to use 4G memory, but it can be achieved only when we have special hardware (we can understand it as a server-level) support, rather than our PC, and/Set

What is PAE forceenable? The following references the original msdn: (http://msdn2.microsoft.com/en-us/library/aa906211.aspx)

On a computer that supports hardware-enabled Data Execution Prevention (DEP) and is running a 32-bit version of the Windows Operating

System that supports DEP, PAE is automatically enabled when DEP is enabled and, on all 32-bit versions of the Windows operating system,

Failed t Windows Server 2003 with SP1, PAE is disabled when you disable dep. To enable PAE when DEP is disabled, you must enable PAE

Explicitly, by using/set NX alwaysoff and/set PAE forceenable.

This means that PAE is automatically disabled after DEP is disabled. However, if you still need to enable PAE when DEP is disabled, you need to use/set PAE forceenable !! While

Not many people understand that 4 GB memory is supported by this parameter!

As for our concerns, How much memory can Vista 32-bit support on our PC? The answer is 3,120 MB, or 3.05 GB! The reason is simple because PCI devices (such as video cards and sound cards)

, Nic, etc.) in the addressing range occupied, vista32 retains the memory address space close to 1 GB to ensure the compatibility of these devices (although many of your machine's addresses may not be used), that is, whether you look

In the system attribute, It is 3G or 3.5g, and the actual memory that can be used is 3G! In addition, Microsoft recommends that you use 4 GB or above memory for home users. You must use Windows2003, XP, and Vista.

The 64-bit version. (Msdn for the original text see http://support.microsoft.com /? Kbid & id = 929605)

Note that, after installing 3G memory, it does not mean that you can use so much, because 32-bit Windows Default applications can only use 2G memory, and the rest are reserved for the system kernel, therefore, you need to add

Add the startup parameter "bcdedit/set increaseuserva 3072" so that Windows can allocate more than 2 GB of memory to the application!

Okay, you should be very clear when talking about this. Don't get 4 GB of memory because it's cheap or it's a lot of money, because it will always waste 1 GB (of course I can't care about this money), (the only drawback is that 3 GB DDR2 cannot be implemented.

Current dual-channel)