According to our experience, win2003 Enterprise Edition 32-bit can support 32G of memory, 64-bit system can support 64G, but 64-bit operating system, many software does not support, so We recommend using win2003 32-bit system, up to 32G of memory, generally enough, if the installation does not support, the installation upgrade to sp2 is generally no problem. Why can Windows 2003 Server support more than 4 G memory? To be precise, the 32-bit version can support 32G of memory. This is because MS develops the PAE function for the Server system, that is, physical address extension. This function can expand the 32-bit address space of the memory to 48-bit or 64-bit, so that the theoretical maximum supported memory is 16 * 1024 * 1024. * 1024G = such a large space, while Microsoft deliberately limited it to 32GB, 64-bit system is limited to 64GB. The inconsistency of the restrictions is to distinguish the difference in version, otherwise no one chooses a 64-bit server system (now almost no enterprise chooses 64bit, 32bit is enough, ^_^). Why is it restricted? 1, no motherboard can now support so much memory 2, now no application needs such a large memory, servers that need large memory are generally used in the country, their servers will not use windows system 3, no test environment Microsoft can not verify After more than 64G of memory, the system is stable Windows Server 2003 Enterprise Edition (Enterprise Edition): * Support 8-node cluster, NUMA; Support 8-way SMP * Memory support: (i386) 32-bit version supports 32GB memory (X64) 64-bit version Support 64GB memory Windows 2003 default only supports small memory mode (maximum 3G) is greater than 3G need to edit Boot.ini plus /pae parameters to open large memory mode to support more than 3G memory, follow the above operation to edit Boot.ini restart still problem is you There is a problem with memory compatibility. Here is an example of 2003 boot.ini: [boot loader] timeout=0 default=multi(0)disk(0)rdisk(0)partition(1)\\WINDOWS [operating systems] multi(0 ) disk(0)rdisk(0)partition(1)\\WINDOWS="Windows Server 2003, Enterprise" /fastdetect /usepmtimer /NoExecute=OptIn /PAE Windows Server 2003 Web Edition: For Fast Develop and deploy web services and applications to provide a web hosting and service platform. Supports 2-way SMP (Symmetric Multiprocessing) system with 2GB of memory. Windows Server 2003 Standard Edition: for small and medium-sized businesses and departmental applications. Support 4 channels of SMP, 4GB of memory. Windows Server 2003 Enterprise Edition: Suitable for central and large organizations, available in 32-bit and 64-bit versions. Support 8-node cluster, NUMA; support 8-way SMP, 32-bit version supports 32GB memory, 64-bit version supports 64GB memory. Windows Server 2003 Data Center Edition: For enterprises that require strong scalability and high availability, there are 32-bit and 64-bit versions. The 32-bit version supports 32-way SMP and 64GB memory; the 64-bit version supports 64-way SMP and 512GB of memory; both versions support 8-node clusters and NUMA. To enable Windows 2003 to support more than 4GB of physical memory, you must add the parameter /pae to In the boot.ini file. When the server was just purchased, it found this problem. Why is the good 4G memory motherboard drama only recognized as 3G? Three-times and four-time modification of the BIOS can only make the motherboard recognize 3.3G and 3.5G, which is really annoying. . . It turns out that some servers have memory holes, so 3.3G-3.8G is normal. This part of the empty memory is consumed as hardware. Too much difference is necessary to upgrade the BIOS of the motherboard and the firmware of the array card. . In the case of the XP or 2003 series, the /PAE parameter must be added to the BOOS.INI to access the extended memory normally. If you exceed 1G, you must add the /USERVA=3030 parameter to optimize the configuration of virtual memory. An important security feature in win2003 SP1 - "Data Execution Protection (abbreviation: DEP)" generated by rdquo;. You can find it in “Control Panel →System →Advanced →Setting →Data Execution Protection”. When you switch between these two, “/NoExecute=OptIn” will also become “/NoExecute=Optout”. Note: This feature requires hardware support: AMD Athlon 64, AMD Opteron, Intel's Itanium and Itanium 2, and companies such as NVIDIA, VIA, and Transmeta are also expected to add the technology to their chips. It is recommended that ordinary users do not modify it, otherwise it will cause the system to run unstable. /NoExecute=alwaysoff is to close the data execution protection function /NoExecute=OptIn means that the first item is selected, that is, only ……” that /NoExecute=Optout indicates that the second item /noexecute=AlwaysOff is selected When it is equivalent to turning off the DEP and EVP functions, all programs blocked by it can run normally /NoExecute=OptOut --DEP is opened, and all services use dep v. If your server memory is greater than 3G, the system is Win2003 If you don't support 3G or more, you can take a look at this article. This article introduces Physical Address Extension (PAE) and Address Windowing Extension (AWE) and explains how they work together. This article also discusses memory usage limits beyond the 4 GB range inherent in 32-bit operating systems. MORE INFORMATION PAE improves the ability of the IA32 processor to handle more than 4 GB of physical memory. Microsoft Windows 2000 Advanced Server, Microsoft Windows 2000 Datacenter Server, Microsoft Windows Server 2003 Enterprise Edition, and Microsoft Windows Server 2003 Datacenter Edition can use PAE to take advantage of more than 4GB of physical memory. To enable PAE, you need to use the /PAE parameter in the Boot.ini file. Note: PAE is automatically enabled in Windows Server 2003 Enterprise Edition and Windows Server 2003 Datacenter Edition only when the server uses hot-add memory devices. In this case, you do not need to use the /PAE switch on systems that are configured to use hot-add memory devices. In other cases, you must use the /PAE switch in the Boot.ini file to take advantage of more than 4GB of memory. Typically, processes running under Windows 2000 or Windows Server 2003 can access up to 2 GB of memory address space (assuming the /3GB parameter is not used), some of which are physical memory and others are virtual memory. The more programs you run (and therefore the more processes), the closer the memory address space is to the 2 GB maximum. When this happens, the paging process will increase significantly and have a negative impact on performance. The Windows 2000 and Windows Server 2003 memory managers use PAE to provide more physical memory to the program. This reduces the need to swap page file memory, which improves performance. The program itself does not know the actual memory size. All memory management and PAE memory allocation are handled by the memory manager, regardless of the program being run. The above information is valid for running programs when using the /3GB parameter. Programs that require 3 GB of memory are more likely to have more of their required memory in physical memory than in paged virtual memory. This will enhance the performance of programs that can use the /3GB parameter. The exception is when the /3GB parameter is used with the /PAE parameter. In this case, the operating system will not use any more than 16 GB of memory. This behavior is caused by the kernel virtual memory space considerations. Therefore, if the system reboots with the /3GB entry in the Boot.ini file and the system has more than 16 GB of physical memory, the operating system does not use additional physical random access memory (RAM). If you do not use the /3GB switch when you restart your computer, you will be able to use all of the physical memory. AWE is a set of application programming interfaces (APIs) for memory manager functions that enable programs to address more memory — 4 GB of memory than standard 32-bit addressing. AWE enables programs to reserve physical memory as non-paged memory and then dynamically map non-paged memory portions to the program's memory working set. This process enables memory-intensive programs, such as large database systems, to retain large amounts of physical memory for data without having to swap paging files for use. Instead, the data is exchanged in the working set and the reserved memory exceeds the 4 GB range. In addition, a memory range beyond 4 GB is public to the memory manager and AWE works through PAE. Without PAE, AWE cannot retain more than 4 GB of memory. The following is an example of a Boot.ini file with the PAE switch added: [boot loader] timeout=30 default=multi(0)disk(0)rdisk(0)partition(2)\\WINDOWS [operating systems] multi( 0) disk(0)rdisk(0)partition(2)\\WINDOWS="Windows Server 2003, Enterprise" /fastdetect /PAE Warning: The contents of the Boot.ini file vary depending on your configuration. For more information, click the article number below to view the article in the Microsoft Knowledge Base: 317526 (http://support.microsoft.com/kb/317526/) How to Edit Boot.ini in Windows Server 2003 In summary, PAE is a feature of the Windows 2000 and Windows Server 2003 Memory Manager that provides more physical memory for programs that request memory. The program doesn't know that some of the memory it is using is in the range of more than 4 GB, just as the program doesn't know that the memory it is requesting is actually in the page file. AWE is an API set that enables programs to retain large blocks of memory. The reserved memory is non-paged and can only be used by the program. For more information about AWE and PAE, click the article number below to view the article in the Microsoft Knowledge Base: 268363 (http://support.microsoft.com/kb/268363/) Address Extension (PAE) If you add more memory to your system, the BIOS may recognize all of the physical RAM installed in the server, and Windows will only recognize some of the RAM. If the server has enabled redundant memory or memory mirroring, all remaining memory may not be visible to Windows. Redundant memory provides a failover block of memory for a system in the event of a memory block failure. Memory mirroring splits the memory block into a mirror set. Both features are enabled or disabled in the BIOS and are not accessible through Windows. To modify the settings for these features, you may have to refer to the system user manual or the OEM website. In addition, you may have to contact your hardware vendor. For example, if a running system has 4GB of RAM installed and then adds another 4GB of RAM, Windows may only recognize 4GB or 6GB of physical memory, not all 8GB. Redundant memory features or memory mirroring may be enabled on new memory blocks if you are not aware of them. These symptoms are similar to the symptoms when the /PAE switch is not added to the Boot.ini file