It looks like someone has generated configuration from IBSurgeon's Configuration Calculator website for Firebird, and then this configuration was modified without understanding how parameters work.

The first recommendation is to use the original configurations generated by Firebird Configuration Calculator web-site.

Then, do the Simple Insert/Update/Delete test for Firebird, to see what it is the baseline for the general performance. If results of sIUD test will be less than average, consider to use better hardware or VM. If results are higher than average, collect trace and analyze longest SQL queries.