Can't See >16MB Under W95? HIMEMUPD.EXE
is the cure!
On an IBM PS/2 Model 77, 90 or 95 computer with more than 16 MB of memory
(RAM) installed, Windows 95 only recognizes and uses 16 MB of memory. This is
because HIMEM.SYS, the extended memory manager, only detects 16 MB of memory
These computers use a nonstandard API for reporting memory in excess of 16
MB that is not supported by Windows 95.
This issue is resolved by the following updated file(s) for Windows 95 and
OSR2, and later versions of these file(s):
HIMEM.SYS ver 3.95 dated 10/2/95 33,127 bytes.
This and later versions of HIMEM.SYS support the API used by the computers
listed in this article for reporting memory in excess of 16 MB.
Microsoft has confirmed this to be a problem in Microsoft Windows 95. An
update to address this problem is now available, but is not fully regression
tested and should be applied only to computers experiencing this specific
problem. Unless you are severely impacted by this specific problem, Microsoft
does not recommend implementing this update at this time. Contact Microsoft
Technical Support for additional information about the availability of this
This issue is resolved in Microsoft Windows 98.
The computers listed in this article use INT 15 ax=c700h to report memory
above 16 MB. (Other IBM PS/2 Micro Channel computers may use INT 15 ax=E881.)
The updated version of HIMEM.SYS accepts a /P switch that causes HIMEM to use
this API to detect memory in excess of 16 MB. Without the /P switch, the
updated HIMEM does not use this API, and functions the same as the shipping
version of HIMEM.
The new version of HIMEM.SYS reports itself as version 3.95, the same as the
shipping version. Knowledge Base Reference Article: Q137755: No More Than 16 MB
of Memory Reported on IBM PS/2 Model 77, 90.