More than 2GB RAM useless with 32bit XP?

[DHC6twinotter]

Hey folks,

I'm hoping some of you can clarify this for me. I'm running Windows XP Pro with 2GB RAM, and I would like to upgrade to 4. My motherboard can support up to 8, IIRC.

I've been told that anything over 2GB RAM is useless with 32bit XP, and that only the 64bit XP can take advantage of any RAM over 2GB. I've also been told that not many programs are designed with 64bit in mind, so even then, having more than 2GB RAM is useless with 64bit architecture.

Is this true? Can somebody shed some light on this please?

Is there anybody on here running more than 2GB RAM on thier 32bit XP Pro machine?

Thanks!

[randver]

32bit can handle up to 3.5gb. my new laptop came with 4gb but since its a 32bit it only used 3.5 of it wasting the other .5gb

[troyboy162]

i thought there was a patch to allow 32xp to adress more ram? but you will certinly be hitting a point of demishing returns after 2 gb unless your doing special memory intensive programs.

[Good Times]

Daniel,

Read this:

http://www.microsoft.com/whdc/system...AE/PAEmem.mspx

Windows XP Professional and Windows Server 2003 Memory Support. The maximum amount of memory that can be supported on Windows XP Professional and Windows Server 2003 is also 4 GB. However, Windows Server 2003, Enterprise Edition supports 32 GB of physical RAM and Windows Server 2003, Datacenter Edition supports 64 GB of physical RAM using the PAE feature.

[mastacox]

Generally speaking, you will not see any improvement in a 32-bit Windows system with more than 4GB of RAM. Here is a good explanation as to why:

http://blogs.msdn.com/hiltonl/archiv...m-problem.aspx

Due to an architectural decision made long ago, if you have 4GB of physical RAM installed, Windows is only able to report a portion of the physical 4GB of RAM (ranges from ~2.75GB to 3.5GB depending on the devices installed, motherboard's chipset & BIOS).

This behavior is due to "memory mapped IO reservations". Those reservations overlay the physical address space and mask out those physical addresses so that they cannot be used for working memory. This is independent of the OS running on the machine.

Significant chunks of address space below 4GB (the highest address accessible via 32-bit) get reserved for use by system hardware:

• BIOS – including ACPI and legacy video support

• PCI bus including bridges etc.

• PCI Express support will reserve at least 256MB, up to 768MB depending on graphics card installed memory

What this means is a typical system may see between ~256MB and 1GB of address space below 4GB reserved for hardware use that the OS cannot access. Intel chipset specs are pretty good at explaining what address ranges gets reserved by default and in some cases call out that 1.5GB is always reserved and thus inaccessible to Windows.

[Seanz0rz]

now whether or not xp can effectively use more than 2 gigs of ram is up for debate. my experiences with windows tells me that it grows to fill the container. currently my system is using 1.2 gigs of my 2 gigs of ram (ok so there is a virus scan running, 72 megs...) i just restarted this morning, and have nothing unusually memory intensive running. however, ive had XP running fine on 128 megs of ram. it is no secret that windows has awful garbage collection, hence the need to restart about once a week.

64bit xp has gained in popularity, but there are still drivers that are missing, especially for more obscure hardware.

[arjan]

I think when you want to go 64bit, vista is a better option.

Not many companies want to develop driver for 64bit xp since it's a dead end street anyway.
Vista is a different story, it should be around for a while.

I am running it on my (64bit vista ultimate) home pc and it works just fine. I personally never had any issues with vista on either my laptop or home pc. Just make sure the have the horsepower to run it.
Hardware is cheap nowadays, so I don't think it's a big issue.

[DHC6twinotter]

Thanks guys. I'll see if I can understand some of this.

From the link Brian posted, it says this:

• PCI Express support will reserve at least 256MB, up to 768MB depending on graphics card installed memory

What this means is a typical system may see between ~256MB and 1GB of address space below 4GB reserved for hardware use that the OS cannot access. Intel chipset specs are pretty good at explaining what address ranges gets reserved by default and in some cases call out that 1.5GB is always reserved and thus inaccessible to Windows.

I have a 256mb graphics card using a PCI Express x16 slot. Does the above mean that the system has reserved at least 256mb RAM, and maybe more, for the graphics card? I don't have integrated graphics, so I'm not really following this. Does the fact that I have SLI capabilities, but have an unused PCI Express x16 slot make a difference?

From Lance's link, it says there is some sort of "switch" that I may have to turn on?

I'll probably go ahead and get more RAM since it is cheap, but now I'm just really curious about this. I wish I had my PC and the processor and motherboard info handy, but it's all buried in my car with all my other stuff.

Motherboard: ASUS 5PNL-SLI (or something like that)
Processor: Intel E6600 Core 2 Duo
Graphics Card: ATI Radeon All-In-Wonder 2006 (X1300)

[DHC6twinotter]

Also, 2GB RAM has been fine for the most part, but I have done some 3D rendering with AutoCAD and things start getting choppy. Same with a 3D 6000sqft house I drew up on Google SketchUp. I figured RAM was my issue, but maybe it something else. Graphics card maybe? I dunno.

I haven't been too enthusiastic with what I’ve seen of Vista, although I will admit I haven't played with it much. It looks pretty, but I'm not convinced on its reliability. I may be purchasing a laptop in a few months, and I probably have no choice but to run Vista, so I'll see how I like it then. Maybe I'll just have to get a MacBook instead and run XP pro on it.

[mastacox]

Also, 2GB RAM has been fine for the most part, but I have done some 3D rendering with AutoCAD and things start getting choppy. Same with a 3D 6000sqft house I drew up on Google SketchUp. I figured RAM was my issue, but maybe it something else. Graphics card maybe? I dunno.

Those sound like graphics card and/or possibly CPU bottlenecks. I think your RAM has little to nothing to do with rendering 3d graphics.