Firebird 2_5 Performance on Windows 2008 (64 bit) Server

I am experiencing a significant degredation in performance
using Firebird 2_5 on Windows 2008 (64 bit) server

The same client (application) and same database configuration using a 32 bit processor running on XP out
performs the server in the following ratio -

XP performance 20 transactions per sec
2008 performance 5.7 transactions per sec

I would have expected the performance to be the other way
round

Can anyone give me some indication as to what I need to
configure to get the performance of the 2008 server upto
standard ?

I have -
set the affinity to 2 - no improvement
disabled windows fireware

What is your setup? Firebird version etc?
Try to use Firebird x64 SuperClassic (if you have more than one CPU core).
What is windows fireware, BTW? :-) You meant firewall?

Setting the Affinity only works with SuperServer and I hope you aren't using SuperServer in production, especially on a server with multiple CPUs/Cores.

You might run into a problem of Windows 2008 Server, where the file system cache might eat up all available RAM.