Windows XP Professional 4GB RAM Memory?

By AtlBo ·
I have Windows XP (32 bit OS) on a Dell GX270. I am planning to upgrade to 4 GB of RAM memory. My question is: will I have full use of all the memory if I make the upgrade? I've been reading about the issue, and I keep getting conflicting information. Sometimes I read that XP will recognize only 3 or 3.5 GB, sometimes I read that it will recognize all 4 GB. Also, I keep running into mentions of Physical Address Memory. I'm ready to do whatever is best. My graphics card is only 64 MB if the information helps. I also have a soundblaster X-Fi sound card, but I am not sure if that is important. Anyone know the real truth? Any fully educated recommendations would be appreciated. Thanks

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4GB RAM in 32bit Windows

by Who Am I Really In reply to Windows XP Professional 4 ...

Yes the truth is that 4GB is the max. RAM addressable in 32Bit OS,
however, in order to address that RAM the system needs to grab a chunk of that space and use it for addressing the rest of it,
you can see this in any amount of RAM config. if you have 2048MB / 2GB you actually get just under 2GB closer to 1.98GB etc. depending on the system and what's installed, ie. if you have an integrated graphics that uses 128MB or 256MB that also vanishes from the user usable RAM.

My most current system has 4GB of RAM on XP-32bit and an integrated 256MB Intel graphics card, so the usable address space on my system is 3.25GB
the first 512MB going to the system and the 256MB going to the card.

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by mjabadilla07 In reply to 4GB RAM in 32bit Windows

thanks for the brief discussion i learned a lot from it ^__^ by the way I'm just a student surfing the net^__^

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Just a few more details

by TheChas In reply to Windows XP Professional 4 ...

It is easy to get conflicting information about how much RAM a 32 bit system can use as every system is different and the maximum amount of usable as opposed to addressable RAM is very system dependent.

All 32 bit operating systems, not just Windows XP, have a 4GB maximum address space. Ever since 32 bit systems came out, the motherboard and BIOS producers have been making use of the upper memory address space for what boils down to system housekeeping tasks. Be it the PCI bus, or your graphics adapter every device that has a mapped memory address makes use of the upper address space.

All 32 bit systems limit the maximum usable system RAM. The minimum reserved address space varies from 500 to 750 MB with 750 MB being more common. Add a top end graphics card and a number of PCI cards, and the amount of reserved memory address space can exceed 1.25 GB.

Thus, the amount of usable memory on a 32 bit system can vary from 2.5 GB to 3.5 GB depending on how the BIOS is written, and how much hardware is in the system.

It sort of falls under the guideline that individual results may vary.

A couple of side notes:
When people first started installing large amounts of system RAM, many of the BIOS POST memory tests only reported the amount of usable RAM. In order to reduce customer complaints, the BIOS code was changed to report the installed RAM rather than the usable RAM.

Then, Microsoft started getting complaints about why Windows did not report all of the installed RAM. For Vista, Microsoft sent out a patch and now system properties reports installed rather than usable RAM.

So, another way to look at RAM above 3GB on a 32 bit system is sort of like the difference from the decimal bits and the formatted bytes on a hard drive.


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Thanks for the help

by AtlBo In reply to Windows XP Professional 4 ...

I will go ahead with the upgrade for sure now that I know the system will be able to use the memory. Now to upgrade the graphics and "voila" finished computer!

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