asterisk users - Jun 2005 - Load problems

hello,

from time to time my cpu load grows up to 100% and the system becomes
unusable (calls get disconnected, quality is VERY poor, etc.)

the only solution i found so far is to restart the asterisk service,
but it's definitely not  a way of solving the problem.

My * version is Asterisk CVS-HEAD-05/18/05-00:15:59

i have two quad-span E1 cards in this system and it acts as a PBX for
7-to-1 isdn concentrator.

thanks,
Calin.