Win9x: More than 512 MB of RAM?

[Countach69]

Memory management in Windows 98SE partly deals with the SYSTEM ARENA; virtual memory mapped in the C0000000 to FFFFFFFF address space (3 to 4 Gigabyte region). Video RAM (memory on your video card), AGP aperture size (in the BIOS) and VCACHE all reside in this space which is limited to 1 Gigabyte.

This 1 Gigabyte space can get filled rather quickly if you let Windows 98SE manage VCACHE on its own. VCACHE can initialize up to 800 Megabytes thus leaving no room for other devices/program using this region. Look at the SIMPLIFIED example below:

-Computer RAM: Large amount (768M, 1Gig, 1.5Gig etc.)

-Video card RAM: 128 Megabytes

-Size of AGP aperture (in the BIOS): 256 Megabytes

-MAXIMUM left in SYSTEM ARENA: 640 Megabytes (1024 -(128 + 256))

-VCACHE initialize:

-VCACHE says to himself: "This computer has a lot of RAM so lets use a large amount for caching

purposes". Caching simply means it will store a copy of frequently access file in this region of RAM so the next time the computer needs them it will not have to load them from the much slower hard drive. The drawbacks are that this memory is no longer available to run large program/games (simplified explanation).

-If the size VCACHE initializes to at startup is bigger than the amount left in the SYSTEM ARENA, Windows 98SE will not load or will behave erratictly.

Solving this problem involves 2 settings in the SYSTEM.INI file; MaxPhysPage and/or MaxFileCache depending of your particular problem. If you have a large amount of RAM in Windows 98SE and you suspect that it is causing installation problem and would like to limit it to a certain amount then do the following:

If you are installing a fresh copy of windows 98SE

01-Start the installation normally.

02-Upon the FIRST reboot, stop the computer at the DOS prompt using the F8 or CTRL key.

03-Edit the file SYSTEM.INI using the following command: EDIT C:\WINDOWS\SYSTEM.INI

04-Locate the following entry: [386Enh]

05-Add the following string: MaxPhysPage=

05a-After the equal sign use the table below to limit the amount of memory Windows 98SE will use.

05b-Example: MaxPhysPage=30000 would limit the amount of RAM to 768 Megs.

06-Locate the following entry: [vcache]

07-Add the following string: MaxFileCache=100000

07a-The previous line would limit the size of VCACHE to 100000 Kilobytes (100 Megabytes).

07b-Contrary to the MaxPhysPage setting the amount is in decimal format.

07c-Limiting VCACHE to 217 Megabytes would be: MaxFileCache=217000

07d-Lets not split hair with 1 megabyte = 1024 OK!

09-Reboot.

10-Continue the installation normally.

RAM

960 MaxPhysPage=3C000

896 MaxPhysPage=38000

832 MaxPhysPage=34000

768 MaxPhysPage=30000

704 MaxPhysPage=2C000

640 MaxPhysPage=28000

576 MaxPhysPage=24000

512 MaxPhysPage=20000

448 MaxPhysPage=1C000

384 MaxPhysPage=18000

320 MaxPhysPage=14000

256 MaxPhysPage=10000

224 MaxPhysPage=0E000

192 MaxPhysPage=0C000

160 MaxPhysPage=0A000

128 MaxPhysPage=08000

96 MaxPhysPage=06000

88 MaxPhysPage=05800

80 MaxPhysPage=05000

72 MaxPhysPage=04800

64 MaxPhysPage=04000

56 MaxPhysPage=03800

48 MaxPhysPage=03000

40 MaxPhysPage=02800

32 MaxPhysPage=02000

24 MaxPhysPage=01800

16 MaxPhysPage=01000

12 MaxPhysPage=00C00

08 MaxPhysPage=00800

If your Windows 98SE is already installed you can use MSCONFIG.EXE and go in the General Tab, Advanced Settings to limit the size of RAM. For limiting the size of VCACHE use SYSEDIT.EXE.

A little note about MaxFileCache and the MinFileCache settings. These value are NOT meant to be fixed, that is, set a value and forget. They are meant to be adapted to each situation. I like to use very large amount for the cache when testing applications where i have to open and close them frequently. With a small cache i would be accessing the hard drive constantly but not so with a large one. On the opposite, i only have 512 Megs of RAM so when i play a RAM intensive game like Far Cry i use a small value for the cache. Remember allocating RAM to VCACHE means that this memory will no longer be available to run program (simplified explanation).

RAM demanding Games: DOOM3, Quake 4, Far Cry, around 30 Megs allocated to VCACHE.

[vcache]

MinFileCache=30000

MaxFileCache=30000

Everyday tasks, around 150 Megs allocated to VCACHE or as the tasks dictactes 200, 300 Megs etc.

[vcache]

MinFileCache=150000

MaxFileCache=150000

BAD USE of VCACHE with a system with 512 Megs of RAM and playing Far Cry.

With these settings below it would take an enormous amount of time to load Far Cry because there is basically no more RAM available to load the game. Windows would rely on simulating RAM using the hard drive which is incredibly slow. But with a system with 1 Gig of RAM these settings would be perfect.

[vcache]

MinFileCache=350000

MaxFileCache=350000

Countach69

-Specifying Amount of RAM Available to Windows Using MaxPhysPage

http://support.microsoft.com/default.aspx?...kb;en-us;181862

-Computer May Reboot Continuously with More Than 1.5 GB of RAM

http://support.microsoft.com/default.aspx?...kb;en-us;304943

-Error Message: Insufficient Memory to Initialize Windows

http://support.microsoft.com/default.aspx?...kb;en-us;184447

[kartel]

... or one could try to install 98SE2ME:

http://www.msfn.org/board/?showtopic=46349

which installs [options 1 + 2] newer VCACHE.VXD from Windows ME setup CD.

Hope this helps.

Where can someone obtain the ME cab files needed for the .vxd replacement....sounds interesting.

[azagahl]

Where can someone obtain the ME cab files

Ideally, from a Windows ME disc.

[kartel]

Anywhere else ? Maybe the files are availible for download somewhere

Edited December 2, 2005 by kartel

[galahs]

More at Ahuma.org

I used the guide located at http://aumha.org/win4/a/memmgmt.php to get my Pentium 4 with 1.5GB of RAM to run Windows 98SE (it required me to disable my 512MB of my RAM, basically only making 1GB available to Windows 98)