I found the following post in an otherwise unhelpful thread, somewhere out there in the internet:
"Paradox forums are hard to look through. So here is a list of things to do if you are crashing.
* Most obvious is to use a fresh install of CKDV with the latest Beta patch.
(((DVIP + More Kingdoms and/or CKDV gfx mods do not cause crashes or alter performance.)))
* Open up the Settings file and make sure your resolution matches your desktop resolution.
* Rename the avi folder to avi_OFF
* Rename the music folder to music_OFF
(((This will make monthly turns less laggy)))
* Set your Color Quality to 16bits.
(((Don't forget to change it back after...)))
Question: Can CQ be changed to 16/32in a batch file? If so, how?
* If using ffdshow, open the audio decoder configuration, check "Don't use ffdshow in", click the edit box, and type "crusaders.exe" on a new line. Click OK. Do the same thing for the video decoder configuration... I don't know why, it probably serves no purpose, but with ffdshow it is better to be safe than sorry.
* Delete old saves you aren't using.
(((Won't increase performance but will make room for more saves. I think you can only have 12.)))
* Certain places seem to crash more than others IMO. If you are getting a lot of crashes with 1 county/dukedom/kingdom then try starting a game as another that other people on the forums have played without an issue. For example I do not play Vermandois because it crashes a lot for me around 1086.
* Do not post bugs on the forum. Send them to Johan via email with your exceptions, and the savegame, while informing him exactly what the bug is. His email address is on the forum but I think it is johan (at) paradoxplaza.
This will not solve all of your crashes but if you turn the music off you will see a lot of performance increase. If you keep autosave on you can just reload and play a while longer until it crashes again. Alternatively you could keep saving and reloading your game every 3 years to see if that prevents any crashing as it is quicker to reload than it is to run CKDV all over again.
There... now you don't have to go searching around the entire PDX forum if you want to see what advice people have offered."