Please participate in the testing of Firebird performance: below you can find the link to the simple test, which measures INSERT/UPDATE/DELETE performance of the Firebird server. The test is a SQL script for isql.exe: it creates a Firebird database, create a table with several indices, and then inserts, updates and deletes 1 million records. The size of a test database is ~3.6gb, time to run the script is 5-10 minutes, the result is a text output with times and execution statistics.

We found that test result mostly depends on the hardware (disk, CPU) and Firebird cache size: you can see the table with the preliminary results.
Please run the test on your original configuration, and then send the result to include to the table of results.

You can find the test SQL script and all details here.