For people who are comfortable editing their .ini files, I found this on the Bioware fora:
Quote: Posted 10/31/07 12:01 (GMT) by Just a ghost
Sorry for being a bit slow here. I don't completely understand the causes and consequences of the horse stutter yet.
It's client side loading of 13+mb of horse animations. Since the NWN client by default only caches like 16mb in resources, so whenever a horse appears, it causes a momentary stutter as the client has to clear out the resource cache, then load the animation data off the HD. The standard humanoid animations cause no hiccup because you're almost always guaranteed to have it in memory being a PC so it's always loaded.
You can up the amount by changing the nwnplayer.ini setting under [Game Options] and adding "Max Memory Usage=32". Up to a max of 64mb, beyond that there wasn't much performance benefit according to some tests we did internally. So there might be a small initial pause on the first horse load, but afterwards it might not be as bad even if you transition areas.
This leads me to think that adding 'Max Memory Usage=32' or 'Max Memory Usage=64' to your nwnplayer.ini would help significantly with spawn lag. I'm going to give it a try (with 64) and see what I get.
The only other thing I know is that setting it to greater than 64 is almost always counterproductive (reports of dropping to 5fps on the Bioware fora), and you should have a good PC to go to 64, but almost any PC should be able to go to 32 without issues (the default is 16).