>>>>Is anyone successfully running a FoxPro for DOS app on a machine with the new i3-6100 Skylake CPU?
>>>>
>>>>Our old FoxPro 2.6 for DOS app has run happily on 32-bit Windows 7 workstation machines for a long time, but fails to run on the newest replacement workstations that have i3-6100 Skylake processor. Symptoms are that the ntvdm.exe process starts up as expected but then hangs with nothing visible happening in the command window it's running from. The task manager shows ntvdm.exe running at 25% CPU - 100% CPU on the one core that ntvdm.exe is using and nominal CPU % on the other three cores. Memory usage does not fluctuate.
>>>>
>>>>We realize this problem could be due to something else but at the moment we're focusing on the hardware because the network guys can't identify any other differences between these new workstations and the slightly older ones on which the app runs as expected in the same environment.
>>>
>>>You already running the 2.6 patch for fast processors?
>>
>>Thanks for the suggestion, but I believe that patch is for FoxPro for Windows, not DOS. Anyway, processor speed probably isn't the issue here - the app runs fine on other recent PCs with fast processors (>3.0 GHz).
>
>The problem is not CPU speed but multiple CPU cores. If you limit ntvdm.exe to run on 1 core only, it will go away.

Good point. Old but relevant discussion at http://www.markwilson.co.uk/blog/2005/01/troubleshooting-ms-dos-application.htm

How to set affinity in Win7: http://www.tech-recipes.com/rx/37272/set-a-programs-affinity-in-windows-7-for-better-performance/