Bobby Heid
bheid at appdevgrp.com
Thu Aug 31 09:37:49 CDT 2006
Some disjointed information for you... From: http://www.microsoft.com/windowsxp/64bit/overview.mspx <snip> Currently, 32-bit editions of Windows are capable of supporting up to 4 gigabytes (GB) of system memory, with up to 2 GB of dedicated memory per process. Windows Professional XP Edition x64 currently supports up to 128 GB of RAM, with the potential to support up to 16 terabytes of virtual memory as hardware capabilities and memory sizes improve. <snip> And from: http://www.microsoft.com/windowsxp/64bit/facts/top10.mspx Vast memory support The key difference between 32-bit and 64-bit computing with Windows XP is that the 64-bit version can use more system memory. Windows XP Professional x64 Edition supports up to 128 gigabytes (GB) of RAM and 16 terabytes of virtual memory, so applications can run faster when working with large data sets. Physical memory support will grow in the future as hardware capabilities expand. 64-bit vs. 32-bit architecture Address space 64-bit Windows 32-bit Windows Virtual memory 16 terabytes 4 GB Paging file 512 terabytes 16 terabytes Paged pool 128 GB 470 MB Non-paged pool 128 GB 256 MB System cache 1 terabyte 1 GB This shows some of the same info: http://support.microsoft.com/kb/888732/en-us http://support.microsoft.com/kb/888137/en-us The amount of RAM reported by the System Properties dialog box and the System Information tool is less than you expect after you install Windows XP Service Pack 2 Bobby -----Original Message----- From: dba-tech-bounces at databaseadvisors.com [mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of JWColby Sent: Thursday, August 31, 2006 10:05 AM To: 'Access Developers discussion and problem solving'; dba-sqlserver at databaseadvisors.com; Tech - Database Advisors Inc. Subject: [dba-Tech] Using 4 gbytes of RAM Is anyone using a machine with more than two gig of Ram? I am reading things about doing this and there seems to be a lot of confusion on the matter. Much of the confusion seems to come from the fact that until the 64 bit versions of the X86 processors, the "internals" of the processor were all 32 bits which limited direct generation of addresses to 4 gig. All of my machines are 64 bit (AMD) processors so theoretically they can use more than 4 gig but how? Everyone seems to agree that in XP32, only 4 gig is available to work with and that things like video cards and other "machine stuff" eats into that. Thus regardless of anything, you will end up with less than 4 gig due to that, perhaps as little as 3.25 gig. After that, confusion reigns, at least in my mind. Understand that I am discussing Windows XP 32 specifically, although anyone is welcome to chip in what they "know" regarding other windows versions as long as they specify what version they are discussing. The next thing that is discussed is that the OS itself reserves 2 gig for itself (which includes the video etc AFAICT), leaving up to 2 gig for EACH APPLICATION, implying that any application can have / use up to 2 gig. Some claim that if you have 4 gig, the swap file won't be used since that is part of the 4 gig available. It seems illogical since each application can use up to 2 gig. However I have created a separate partition to hold my swap file and tried to create one of 6 gig and Windows refused, limiting the size of the swap file to 4 gig. So I am trying to figure out what the reality is. If a machine has 4 gig physical ram, and "machine stuff" uses (for argument's sake) .75 gig, is the .75 gig of physical ram simply unused? Is it used by the OS for buffers? What about the swap file? If you have a 4 gig swap file, would you have 7.25 "total available memory" for Windows use? Does this indeed then limit the APPLICATIONS to 5.25 gig of "total" memory and 2 gig of physical memory? And what happens if you manage to get (for the sake of argument) 8 gig stuffed into a machine. Some motherboards claim to handle that much but can Windows XP 32 actually use it? Can Windows XP 64? If you need this much memory is Windows XP 64 a way to get at the memory? If you are still using 32 bit apps, will it actually map as much as 2 gig of physical memory to the 32 bit apps so that (for example) 3 high powered memory hungry 32 bit apps actually had 2 gig available to each of them all the time? If anyone has run across any authoritive (on-line) reading on the subject I would love to look at it. John W. Colby Colby Consulting www.ColbyConsulting.com _______________________________________________ dba-Tech mailing list dba-Tech at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/dba-tech Website: http://www.databaseadvisors.com