Windows XP Pro 32-bit? RAM=4GB?

Clarifications

Go with 3GB. You will be much happier with it, if your motherboard can support that much...

Windows XP Pro 32-bit edition has a limit of 4GB's of RAM. Of course you need to make sure that your motherboard can support that much.

The theoretical limit on a 32 Bit Windows OS is 4 GB of RAM. But many motherboards/chipsets reserve some of that memory for other functions, particularly when you use a lot of the built in HW functions like networking, RAID controller, sound controller etc on the MB.

So it does vary from board to board. If I install 4 GB of RAM on mine, I will see 3.5GB.

I'm running XP pro 32 bit today with 2GB. And I run some memory hungry games. I might add another 2 GB.

James

32 bit OS's can see and use up to 4GB RAM.
However, this includes all of the memory used by HW and
video as well. If your video card has memory or uses it
(shared) with the system, this counts against your max
RAM, but it does not get displayed as RAM. Same with
other devices (both MB devices and add-in cards).

I never looked into it too much, but I have read that in XP,
having a max of 2 GB RAM is actually faster than having 3
GB.
Also, I have read that it may be suggested to keep the
4GB because the system still uses it (or part of it) but it is
not available for applications useage. I am not sure if I
beleive this, but you can test it out, is there any
performance hit if you remove 1GB?

Great responses, thanks to all of you.

When I bought this computer HP Pavilion 061, it only had 512MB RAM on it. There are only 2 memory slots inside. I thought the total limit on RAM was 1024. So, now, I have 2 512MB 1024MB (1GB) RAM.

Computer System Info:
OS Name Microsoft Windows XP Professional
Version 5.1.2600 Service Pack 2 Build 2600
OS Manufacturer Microsoft Corporation - 32-bit?
System Name MYCOMPUTER
System Manufacturer HP Pavilion 061
System Model D7222Z-ABA A550Y
System Type X86-based PC
Processor x86 Family 15 Model 3 Stepping 3 GenuineIntel ~2800 Mhz
Processor x86 Family 15 Model 3 Stepping 3 GenuineIntel ~2800 Mhz
BIOS Version/Date American Megatrends Inc. 3.22, 3/19/2004
SMBIOS Version 2.3
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\system32
Boot Device \Device\HarddiskVolume2
Locale United States
Hardware Abstraction
Layer Version = "5.1.2600.2180 (xpsp_sp2_rtm.040803-2158)"
User Name MYCOMPUTER\Administrator
Time Zone Pacific Standard Time
Total Physical Memory 1,024.00 MB
Avail Physical Memory 551.27 MB
Total Virtual Memory 2.00 GB
Avail Virtual Memory 1.96 GB
Page File Space 1.65 GB
Page File C:\pagefile.sys

If I can increase the RAM to 2GB, I would be very happy. But how do I know that my computer will accept 2GB RAM? I don't want to purchase the two 1GB memory modules if my computer won't accept it.

Any suggestions? Trial by error? Very expensive if it doesn't work.

With XP and even Vista, there are both hardware and software limitations.

With a 32 Bit CPU, you have a practical limit of 4GB period. This 4GB includes anywhere from 500MB up to 1GB that must be reserved for system resources such as the PCI bus.
So, the functional limit with a 32 Bit CPU is 3GB with either Windows XP or Vista.

The published limits you see at Microsoft for different versions of Windows are based on the limits of the OS itself, and do not take into account the hardware limitations.

This is not all that different from the 512MB limit for Windows 98 and Me. Except that with XP and Vista, they don't choke when you install more RAM.

Also, you have the working limit. That is, there is a magic amount of RAM where the OS performs at it's optimum. Paradoxically, adding more RAM beyond the range of optimum performance can actually make the OS run slower than when there is less RAM.

As to your primary question, the amount of RAM that it is worth installing depends on what your motherboard supports.

If you are running a 32 Bit CPU, I would stop at 2GB of RAM.

If your motherboard supports dual channel mode, you might want to install 4GB in 2 banks of 1GB modules both in dual channel mode.

Chas

You can only install the amount of memory supported by your motherboard. If motherboard supports less than 4GB, that's your limit.

It is not memory that is reserved, it is addresses. PCI cards, video cards, motherboard resources, and other devices use addresses. To see what's happening, in Device Manager view by Resources and then expand I/O. Those are the addresses used and are not available to address RAM.