It is normally the power saving features of Laptops that cause the issues and because Laptops are designed to run from batteries these are often very hard to disable completely.
I use Via Pico mobos in my lathe and one of my mills, they dont have parallel ports but I use the SmoothStepper anyway so that doesnt concern me. I am also redoing the Bridgeport at the moment and I am using a micro ATX mobo. Although I am again using an external controller with this retrofit I did run the driver test at 100KHz to see what it was like and it is the smoothest I have ever seen on any computer at any frequency, so although I havent actually tried it with the parallel port I would be confident that it would be flawless.
The mobo is an Asus AT5NM10-I
Hood