Specifying Amount of RAM Available to Windows Using MaxPhysPage

 Last reviewed: February 27, 1998
Article ID: Q181862
The information in this article applies to:
  • Microsoft Windows 95

SUMMARY

This article contains a table of MaxPhysPage values you can use to limit the amount of random access memory (RAM) available to Windows.

MORE INFORMATION

To use the MaxPhysPage entry to specify the amount of RAM that is available to Windows, add the following line in the [386Enh] section of the System.ini file 

   MaxPhysPage=<nnn>
where <nnn> is a hexidecimal number that determines the number of memory pages available to Windows. A page is 4096 bytes of RAM for 486 and Pentium processors.

When the MaxPhysPage entry is used, the following formula is used to determine the amount of RAM available to Windows: 

   4096 X MaxPhysPage (decimal) = Amount of RAM available to Windows in 
   bytes
Therefore, to limit Windows to 32 MB of memory, use the following formula to determine the MaxPhysPage entry: 

   (32 * 1048576) / 4096 = 8192 (decimal) or 02000 (hexadecimal)
NOTE: One megabyte is 1,048,576 bytes.

The following table list some common RAM amounts and the corresponding MaxPhysPage entry: 

   Amount of RAM
   Available to Windows (MB)  (Bytes)           MaxPhysPage Entry
   -------------------------  -------------     -----------------
   960                        1,006,632,960     MaxPhysPage=3C000
   896                        939,524,096       MaxPhysPage=38000
   832                        872,415,323       MaxPhysPage=34000
   768                        805,306,368       MaxPhysPage=30000
   704                        738,197,504       MaxPhysPage=2C000
   640                        671,088,640       MaxPhysPage=28000
   576                        603,979,776       MaxPhysPage=24000
   512                        536,870,912       MaxPhysPage=20000
   448                        469,762,048       MaxPhysPage=1C000
   384                        402,653,184       MaxPhysPage=18000
   320                        335,544,320       MaxPhysPage=14000
   256                        268,435,456       MaxPhysPage=10000
   224                        234,881,024       MaxPhysPage=0E000
   192                        201,326,592       MaxPhysPage=0C000
   160                        167,772,160       MaxPhysPage=0A000
   128                        134,217,728       MaxPhysPage=08000
   96                         100,663,296       MaxPhysPage=06000
   88                         92,274,688        MaxPhysPage=05800
   80                         83,886,080        MaxPhysPage=05000
   72                         75,497,472        MaxPhysPage=04800
   64                         67,108,864        MaxPhysPage=04000
   56                         58,720,256        MaxPhysPage=03800
   48                         50,331,648        MaxPhysPage=03000
   40                         41,943,040        MaxPhysPage=02800
   32                         33,554,432        MaxPhysPage=02000
   24                         25,165,824        MaxPhysPage=01800
   16                         16,777,216        MaxPhysPage=01000
   12                         12,582,912        MaxPhysPage=00C00
   08                         8,388,608         MaxPhysPage=00800
For additional information about MaxPhysPage, please see the following Articles in the Microsoft Knowledge Base: 

   Article-ID: Q134503
   TITLE     : Parity Error Messages May Indicate Bad Memory

   Article-ID: Q83436
   Title     : Windows 3.1 Resource Kit SYSTEM.INI [386ENH] Section M-Z

Additional query words: how to
Keywords : win95 kbenv
Version : WINDOWS:95
Platform : WINDOWS
Issue type : kbhowto

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Last reviewed: February 27, 1998
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