Is it normal for Gbak to perform very slowly under classic server?
If not do you have any suggestions as to what might be wrong?
There seem to be lots of pauses in the execution, Using Superserver
on the same machine and DB performs much faster. At the time of the
backup GBak has exclusive access to the DB so I don't think this is a
concurrency issue.

Best Regards,
Will.

Server Dual Xeon 2.8 GHz with hyperthreading.
1GB Ram (700mb in use)
Firebird 1.5.3.4870