NPC Lag and Crashes

Server Spec:

amd athlon x2 5000+
2 gb ram
win xp sp3

If we set the FLserver.exe to just one core everything is fine, but if we have it for both cores the npc’s have very jerky movement.
Note: This is a pain if a program auto restarts FLserver.exe because it just goes to both cores.

Now for some reason when we go to one core FLserver.exe crashes until we remove FLhook from the dacom file (can’t remember the name atm).

Does anyone have theories or fixes for this?