Greetings,
There is a new patch coming up that should fix the intermitent crashes as well as some other things. We are planning for an early morning patch. Sunday 11/24/2007 8AM EST. The unfortunate/ugly part of this new patch is that it will require you to download a new IrthLaunch.exe program. I'll put up a link for that immediately following the patch shutdown tomorrow morning. Other than that the actual patch will not be that large.
We will try to address the lag issues as well tomorrow.
PS. The current problem with the GeForce drivers causing the terrain to look funny can be fixed by going to the display options dialog and turning down the shadow level. We'll get a real fix for that in the next few days.