Not compatible with 686_p.exe

Software entity

686_p.exe accompanies Cyrix CPUs to fool Windows into believing a Pentium chip is present. Some games work if it's disabled but crash if it's running.


The first video game about Not compatible with 686_p.exe was released in 1997.

Many affected games received patches to correct this issue; others did not. Please use tag note if a fix was released.

Removing 686_p.exe from AUTOEXEC.BAT will bypass the problem if the game will actually run on a Cyrix CPU. Please use tag note if this was the publisher's official workarround (instead of or in also a patch)

686_p.exe crashes might seem to be a hardware issue but it really is each piece of software demanding its own way and lying to the other software in an attempt to get it.

Specifically, when running on a Cyrix CPU, 686_p.exe tells to Windows it's running on a Pentium. So Windows tells the software, "I'm running on a Pentium". The game wants to run faster, of course, so rather than using baseline x86 code (that definitely runs on Cyrix, AMD, Transmeta, etc) it uses optimal Pentium code to get the answer to say, "1+1", to which the Cyrix dutifully returns "=Plugh" and the game crashes.


Windows 2

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cdrom directx directx3 glide3d mame rpgmaker win95