32-bit system X86 can support a large amount of memory

Microsoft's latest Windows Server 2008 R2 and the latest Microsoft Office SharePoint (MOSS) Project Server Exchange Search Ser Almost all of the mainstream server products, such as ver 2010, are no longer available in 32-bit versions, and the next version of Windows 8 is said to be only 64-bit. It can be said that the 64-bit era has really come (although from 80386 Times (1985) 16 to upgrade to 32-bit has been over 25 years, it's been like a few centuries in the IT world, but lately there have been some customers struggling between 32-bit and 64-bit choices, So give us a list of the maximum memory support for the 32-bit system, and find out where the Doomsday 32-bit system is.

32-bit Windows uses 4 GB of virtual address space, where 2 GB is allocated to user-mode processes (for example, applications), and 2 GB is allocated to kernel-mode processes such as the operating system and kernel-mode drivers. The system can only support 4G of physical memory. As you know, the operating system retains high 2G addressing space for security, and the virtual memory address of each standalone application is low 2G, as most of you may know.

In addition, there are ways to enable X86 applications to access more memory space:

1. Server-side operating systems such as Windows 2000, Windows 2003, Windows 2008, and so on, can address additional memory with a hardware-compatible PAE (physical addressing Extension) physical addresses extension. As in Boot.in, open by/PAE:

Operating system

Maximum memory capacity after PAE is supported

Windows Advanced Server

8 GB of physical RAM

Windows Datacenter Server

GB of physical RAM

Windows XP (all versions)

4 GB of physical ram*

Windows Server 2003 (and SP1) Standard Edition

4 GB of physical ram*

Windows Server 2003 Enterprise Edition

GB of physical RAM

Windows Server 2003 Datacenter Edition

GB of physical RAM

Windows Server 2003 SP1 Enterprise Edition

GB of physical RAM

Windows Server 2003 SP1 Datacenter Edition

128 GB of physical RAM

2. The server version of Windows 2000, Windows 2003, Windows 2008 can also be opened by opening the startup option of the 3GB switch (such as in Boot.ini/3GB), so that the single process of addressing space to 3G, than not set 2G more out of 1G, A lot of server application performance, indeed can improve a lot (50%)

3. Some special applications have some unique skills for bypassing the operating system using memory, such as Address Windowing Extensions AWE for Microsoft SQL Server Enterprise Edition (2000 2005 2008, 32-bit editions are supported). Windowing Extensions) technology, the memory cap is similar to PAE.

Said X86 turned to say X64, although there is a saying that the current x64 is not really using the 64-bit address bus, but 48 bits, so the memory limit is 2^48. However, the X64 memory addressable space up to 16TB, and in the relevant operating systems and processors, the application can use a addressable space of up to 8TB, not only to the development and compilation of many applications, produce immediate and obvious benefits for the general user, It is the most valuable solution to be able to use the x86 architecture on the basis of backward compatibility (the vast majority), thereby achieving a significant increase in the efficiency of the application.