Firebird slow? Well, maybe it is Windows fault.
So, you just moved to that new cool server, with lots of RAM, Windows and Firebird 64bits, but suddenly you found that Firebird performance gets worse and worse. When you check TaskMan, you see that 99% of the RAM is being used (and so, swap is going on). If you close Firebird process, RAM usage seems to be back to normal. Weird, uh?
First, you may think this is the common problem of Classic/SuperClassic with too many connections and crazy buffers value… but, you checked all the settings, and everything is ok.
If this happening to you, take a look again in TaskMan (or Process Explorer), and check how much memory the OS Cache is consuming. If you find something abnormal, like if it is consuming almost all of your physical RAM, you should take a look at this: http://support.microsoft.com/kb/976618/en-us
Or, if you just moved to that new cool server, or even if you have a little old server, please, give a look to http://www.debian.org/ or http://www.centos.org/ (or the one you choose, freely). Really honor the strength and stability of Firebird.