If you purchased Spear of Destiny and played it without making any modifications, you probably noticed that it's somewhat jittery and not butter smooth like it should be. The source of the problem lies within the game's DOSBox configuration file.
To correct this, first navigate to the following directory: Program Files\Steam\steamapps\common\Spear of Destiny\base
Now, find the SOD.conf file and open it with Notepad.
In the [sdl] section at the top, change fulldouble from true to false. This alleviates screen flickering caused by the next tweak and makes the game's sprites less blurry and more "crisp" like they should be.
Finally, scroll down until you reach the [cpu] section. Change cycles from auto to max and save your changes before closing the file.
The next time you play Spear of Destiny, it should run smooth as butter. This never should have been an issue and could've been avoided had the folks behind the Steam releases at id Software actually tested their games and compared them to how they were years ago on machines that were capable of running them properly. That little rant aside, I hope that you enjoy this little tip and that it makes your Wolfenstein 3D sessions more enjoyable!