[comp.windows.ms] Should DOS apps run slower under Windows

KRW1@NS.CC.LEHIGH.EDU (Kevin Weiner) (06/24/91)

DOS apps will generally run slower under 386 enhanced mode, even
if running as exclusive.  Enhanced mode virtualizes much of the
system hardware, and depending on what the app uses, slowing can
be significant.  For example, rapid checking of the system timer
(normally low overhead) causes a slew of virtual machine activities.
Another major speed factor is the extent to which the app uses
standard DOS services and memory-resident drivers, all of which
require mode switches between protected and real mode.


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Kevin Weiner   Lehigh University Computing Center   (215) 758-3991

tomr@dbase.a-t.com (Tom Rombouts) (06/25/91)

If it interests anyone, I grabbed TAME v. 2.5 from the win3/util
section of "garbo"  (Filename was tame250.zip)  This explains
how to determine how often various DOS apps such as Lotus 1-2-3
poll for keyboard input, and apparently lets you reduce this
somewhat to make some DOS apps run a bit faster in Windows.

I have not used this much, but would certainly suggest it to anyone
trying to tweak DOS app performance under Win3.  Unlike some of
these things, the TAME documentation is comprehensive and very
readable.


Tom Rombouts  Torrance 'Tater  tomr@ashtate.A-T.com