jtr1962
Flashaholic
I recently upgraded from a vintage 2003 A7N8X-E motherboard to an Asus F2A85V-Pro. I installed 16 GB and am currently using Windows 7 64 for my main O/S. I also need to occasionally boot into my old XP install because my parallel port EPROM programmer doesn't work on Windows 7. Anyway, I noticed that XP could only see at most 3.42 GB of the 16 GB installed RAM (this was with a 32 MB frame buffer-XP sees less than 3.42 GB with higher frame buffer settings). Of course, this was expected. PAE is enabled on my XP install. In theory this allows access to up to 64 GB but Microsoft restricted access to 4 GB starting with XP SP2, allegedly because of driver compatibility issues. This essentially meant over 12 GB of my RAM went to waste whenever I booted into XP. Now let me state that I only had 3 GB in my old system and it was usually enough. In fact, I didn't even bother using a pagefile. I was told this might cause problems, but in 6 years of running without a pagefile I never experience any.
Regardless, I wanted to see if there was some way to make use of the wasted RAM. Fortunately, I came across the Gavotte Ramdisk Utility yesterday when googling if it was possible to get XP to use more than 4GB of RAM. While you can't (unless you have SP1 and enable PAE), you can still make use of otherwise unaddressable RAM with this utility because it can access RAM over the 4 GB barrier, even with a 32-bit O/S. With the Gavotte Ramdisk Utility I can make a 12.47 GB ramdisk. I can then enable the pagefile and place it on the ramdisk. XP limits pagefile size to 4095 MB but nothing prevents you from setting up more than one pagefile on your ramdisk. Here's how:
Just open regedit and go to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Session Manager\Memory Management key. In the "PagingFiles" multi-string value paste the following:
Z:\pagefil1.sys 4095 4095
Z:\pagefil2.sys 4095 4095
Z:\pagefil3.sys 4095 4095
This assumes that Z is your ramdisk. Modify as needed for your particular case. You can use the numbering scheme shown to have fewer or more pagefiles as needed, depending upon the space available on your ramdisk. Granted, it's gross overkill but now I can make use of most of my 16 GB in XP. Task Manager now shows a commit charge limit of 15536 MB. I left about half a gig free on the ramdisk for temp files, browser cache, and so forth but I could have used that also for paging if I wanted to.
Chances are good I'll probably never use much over 3 GB when in XP. However, at least now I don't have to worry if I go over that. Also, by setting up a pagefile I no longer have to worry about any issues associated with not having one.
If you have a motherboard which supports > 4 GB of RAM and you're running a 32-bit O/S (either as your primary or secondary O/S), you can now make use of RAM over the 4 GB barrier which would otherwise go to waste.
Regardless, I wanted to see if there was some way to make use of the wasted RAM. Fortunately, I came across the Gavotte Ramdisk Utility yesterday when googling if it was possible to get XP to use more than 4GB of RAM. While you can't (unless you have SP1 and enable PAE), you can still make use of otherwise unaddressable RAM with this utility because it can access RAM over the 4 GB barrier, even with a 32-bit O/S. With the Gavotte Ramdisk Utility I can make a 12.47 GB ramdisk. I can then enable the pagefile and place it on the ramdisk. XP limits pagefile size to 4095 MB but nothing prevents you from setting up more than one pagefile on your ramdisk. Here's how:
Just open regedit and go to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Session Manager\Memory Management key. In the "PagingFiles" multi-string value paste the following:
Z:\pagefil1.sys 4095 4095
Z:\pagefil2.sys 4095 4095
Z:\pagefil3.sys 4095 4095
This assumes that Z is your ramdisk. Modify as needed for your particular case. You can use the numbering scheme shown to have fewer or more pagefiles as needed, depending upon the space available on your ramdisk. Granted, it's gross overkill but now I can make use of most of my 16 GB in XP. Task Manager now shows a commit charge limit of 15536 MB. I left about half a gig free on the ramdisk for temp files, browser cache, and so forth but I could have used that also for paging if I wanted to.
Chances are good I'll probably never use much over 3 GB when in XP. However, at least now I don't have to worry if I go over that. Also, by setting up a pagefile I no longer have to worry about any issues associated with not having one.
If you have a motherboard which supports > 4 GB of RAM and you're running a 32-bit O/S (either as your primary or secondary O/S), you can now make use of RAM over the 4 GB barrier which would otherwise go to waste.