Thingleaf Posted September 17, 2007 Share Posted September 17, 2007 Goddagens! Satt och pulade med min nya Vistaburk när jag upptäckte nåt (enligt mig) mycket märkligt! Överallt där internminnet visas så står det 3Gb eller 3069 Mb eller liknande. Men datorn ska innehålla 4Gb ram och det går inte för allt i världen att se! Kontaktade Dell supporten (XPS-varianten) och frågade om det var nåt fel. Detta är svaret jag fick! Ursäktar redan nu för ett långt svar, men jag tror att det kan vara matnyttigt för gänget här på forumet! Hoppas det iallafall! ;D Hello Mr Tinglof Here is the information about the 4GB issue on Vista 1) Summary on Windows Memory Limitation: Windows was updated some years ago to reserve a certain amount of memory when it has the luxury of 4 gigs of memory to work with: according to Microsoft, this was done to make compatibility for hardware drivers easier (these drivers are what makes the computer and windows work with items like graphics or sound card and some other internal hardware). Windows then reports it to you as if the memory it reserved just isn't there. If there was nothing else there outside window to reserve memory, windows would tell you that you have slightly above 3 gig available. If windows doesn't have these 4 gigs to play with, it doesn't reserve the memory at all, reports it correctly and just uses memory as it needs it. What is happening at the same time though, is that your graphics card is also reserving memory. The graphics card needs this memory all the time, and this happens outside of the 4 gig issue. So when you have 4 gigs in, windows takes nearly 1 gig in reserve, and the graphics card takes slightly more than a half a gig, leaving you with around 2.5 gigs. None of this happens at 2 gig or below, as the graphics card does have its own limited memory. Microsoft do recognise this but there are no fixes for Windows XP, as these changes to Windows were made before 4 gigs of ram in a system was commonplace or even expected. There is a fix for Vista listed below. http://technet.microsoft.com/en-us/library/bb457155.aspx http://blogs.msdn.com/hiltonl/archive/2007...not-4gb-ram-pro blem.aspx http://support.microsoft.com/kb/888137/en-us 2) Memory Limitation Detail : On a system configured with 4 GB of random-access memory (RAM), Microsoft® Windows® reports 3.0 to 3.8 GB of available memory. The same behavior is seen in Linux and other operating systems, as this is a limitation of 32-bit addressing used in IA-32 systems. <<Picture (Device Independent Bitmap)>> NOTE: At this time, Dell portable systems reserve 1 GB of memory for input/output (I/O) space in the basic input/output system (BIOS), making the total memory available 3,000 MB, which equals 3 GB. This is set in the BIOS and cannot be changed by the user. This is a limitation of a 32-bit architecture. The system can only address 4 GB of allocated memory. Allocated memory is made up of physical RAM, and any I/O space needed by devices. The way memory is allocated is that starting at 4 GB, the system allocates device I/O addresses working its way down. Normally this is not a problem, but when systems have 4 GB of physical memory, the addresses needed to address RAM overlap the space needed for I/O. In this case, the need for I/O space takes precedence, and the amount of RAM visible to the operating system and applications is limited to 4 GB minus I/O space. Examples of devices that consume I/O space are: * System BIOS * PCI Express configuration space and memory for PCI Express device(s) * Memory mappy I/O * Motherboard Resources (I/OxAPIC) * Chipset * PCI Enumeration For example: If you have 4GB of system memory, an Intel 915g Express chipset, Windows XP with Service Pack 2, and a PCI Express graphics card the remaining system memory as reported by System Information would be ~3.25GB. The same configuration but with 2GB of system memory would result in all 2GB being available. This is due to the limited capability of memory mapping (or limited amount of addresses) on 32-bit architecture systems. <<Picture (Device Independent Bitmap)>> NOTE: Server systems are able to extend the address space with physical address extension (PAE) . This option is not available on desktop and workstation systems. 3) Fix for Vista Below: Enable support for 4GB of RAM (or more) in Vista 32-bit On a computer that has 4 GB of RAM, the System Properties dialog box and the System Information dialog box may report less memory than you expect. This problem occurs because the address space is limited to 4 GB in a 32-bit hardware environment. Memory may be relocated to make room for addresses that the basic input/output system (BIOS) reserves for hardware. However, because of this limitation, Windows Vista cannot access memory that is relocated above the 4 GB boundary. Solution: Open an elevated Command Prompt, type BCDEdit /set pae ForceEnable and press Enter. The pae parameter enables Physical Address Extension (PAE). On 32-bit versions of Windows, PAE is disabled by default. PAE is an addressing strategy that uses a page-translation hierarchy to enable systems with 32-bit addressing to address more than 4 GB of physical memory. PAE also supports several advanced system and processor features, such as Data Execution Prevention (DEP; "No execute"), Non-Uniform Memory Architecture (NUMA), and hot-add memory, so it is also used on computers with less than 4 GB of memory. PAE must be supported by the processor. On a computer that supports hardware-enabled Data Execution Prevention (DEP), PAE is automatically enabled when DEP is enabled and automatically disabled when you disable DEP. To enable PAE when DEP is disabled, you must enable PAE explicitly: Open an elevated Command Prompt. Type BCDEdit /set nx AlwaysOff & BCDEdit /set pae ForceEnable and press Enter. Thanks, Regards Karl Payne XPS Support Specialist Där ser man! Quote Link to comment Share on other sites More sharing options...
hez Posted September 17, 2007 Share Posted September 17, 2007 32bit system klarar bara 3gb ram, måste ha 64bit om man ska ha mer, men du har ingen nytta av 4gb ram om du inte använder 64bit program som behöver så mycket Quote Link to comment Share on other sites More sharing options...
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