Disclaimer: I haven't got Civ III, but this fix has proved useful for other games where similar symtoms arose. Some people with the problem need to try it out and post their findings:
Microsoft left debug mode on in directx 8 and 8a for DirectSound. That is eating up CPU cycles from hell having that on, not to mention the software/hardware conflicts that it can create. Well, I hope this helps some people. This will cure many ailments.
download:
**
http://www.gamevoiceclub.com/Download/dxapplet.zip **
{note --this is a directx control panel applet, if you have it, then no need to get it again.}
Extract to:
..\Windows\System
go to Control Panel, click on the Dx applet
go to the DirectSound tab and slide the debug slider all the way to the left <<<<<<< to disable debug mode.
note: It does work w/ 8.1 but in some instances, debug is already off with that version.
May help for those experiencing crippling stutter-chop problems and using DirectX 8.x
