Thanks for the input.

I have now upgraded the OS to i86_64 (FC9), and I configured without libcurl, as recommended by Anthony. The FS loaded without problems apart from some “database is locked” errors, which may be harmless? I ran the ulimit as recommended to unlimit all resources.  I started the FS after the ulimit. The same performance test showed a slightly better result. Without trying to make this too scientific, the improvement by going from 32 bit OS to 64 bit OS has been 10-20%, at the most. Still the performance is around 30-40% of the performance of Asterisk.

With 100 a-leg (no b-leg, as all calls are answered by the echo application) permanent channels the CPU idle is 10%, with 60% system-load and 30% CPU-load. So something is rotten in Denmark… /Jon