Subject Configuring Firebird for high transaction through put

We are having to gear up one of our web apps for a potential spike in access next month and have been running some load testing. Overall it seems not to bad but the database is a bit of a bottleneck or so it seems.

Without turning off forced rights what else should we look at? We have increased core utilisation. Does page size have an impact? Any ideas would be welcomed. Are there any documents anywhere that cover this?