Sorry,
I have found the option "Superclassic" - after changing the option to
classic-server!
Here are the results of my testing:
Firebird-Version seconds Query A seconds Query B
2.1 classic-Server 15 7
2.5 superserver 12 7
2.5 superclassic 12 7
Certainly, I have on my local machine only 2 cores! All results was taken on
my local machine.
I'm still interested, which option is the best in your opinion. And what
about the switch? instsvc install -multithreaded
There are another options in firebird.conf to change? (default cache page to
75)

Thanks

please disregard my previous message.