I knew about the memory limit in Windows XP before I went ahead and upped the memory in my Mac from 2GB to 4GB. I just knew that XP would not manage to cope with 4GB even though the limit on 32bit (standard) Windows XP is 4GB. This is because, in Microsoft’s words:
The physical address space is used to address more than just RAM. It is also used to address all of the memory and some of the registers presented by devices. Consequently, if a machine is configured with the maximum amount of physical memory, some of that memory will be unusable because some of the physical address space is mapped for other uses.
I carefully added the memory to my MacBook Pro. If you are not sure how to do this watch the video at the end of this post. Then I rebooted and bingo, OS X reports ‘4 GB’, so I try Windows and it reports 2.98 (some people see 3.25 or around that, Windows reports different numbers for some reason). I disable my swap file and reboot, still only 2.98. I enable the swap file and hard set it to 32MB.
I use Windows for gaming, so it’s important to me that I get the dumb OS to see as much of the memory as I can, so I turn to Google and start researching. It turns out that Windows XP can cope with 4GB of installed memory, but not use it, it uses 2GB to address to games/applications and holds a GB back for the OS. But you can manually edit the Boot.ini file and have Windows use 3GB for games/applications and still hold 1 GB back for the OS.
Here’s Microsoft’s own instructions for the PAE switch:
To enable PAE:
• Locate the Boot.ini file, which is typically in the root folder (for example, C:/) and remove its Read-Only and Hidden attributes.
• Open the Boot.ini file with a text editor, and then add the /PAE parameter to the ARC path, as shown in the following example:
\WINNT=”Windows ???? Datacenter Server” /PAE /basevideo /sos
• On the File menu, click Save.
• Restore the Read-Only attribute to the Boot.ini file.
Instead of PAE you can also use ‘/3GB’. Note that like the PAE switch, this strips memory away from the OS to give more to the applications, it will not make more memory available overall.
Finally, a third option, you can also try the ‘/nolowmem’ switch. Let me know which works best for you and I’ll update this post.
How do you make that 4GB fully usable in Windows XP 32bit? You can’t, unless you switch OS. Linux (64bit versions), OS X, Windows XP 64, Vista 64 and so on. Windows XP 32bit is getting old it seems.
Here’s how to add memory to your MacBook Pro:
38 posts in the queue and what do I do? I write another! Go me for time management!