> The processor is a dual core, but I have run this app on dual-
> core on XP pro without having loss of performance. I'm aware
> of the problem with hyperthreading on Xeon servers and I always
> use Classic version of Firebird on it
> I'll try both suggestions, setting affinity and using Classic
> version of Firebird with that CPU.

I _definitely_ experience the problem under both XP and 2000
(have not tried Vista). I have _definitely_ experienced the
problem regardless of the affinity setting (the default install
will have affinity to only the first CPU). I have _definitely_
experienced the problem on Xeon servers with and without
hyperthreading enabled. I have _definitely_ experienced the
problem on AMD dual-core CPUs. (IOW it is a Firebird bug that
relates to the existence of two processors and not a hardware
compatibility issue.)

There is/was a very specific problem (quite separate to the
known and very old cpu-thrashing problem) and AFAIK a fix was
found and applied to v2 (but it was not practical to back-port,
I asked! :-). [The old cpu-thrashing problem is still not
solved.] During this problem the CPU does nothing, the
server process seems get itself into a blocked state, sometimes
it seems able to wake itself or you can wake it up by doing
something (anything) via a separate connection to the same
server process.

It is highly variable in it's impact, if you dont know to look
for it you may not even see it... when you are lucky. When you
are not so lucky it can be very VERY annoying.

Good luck.

--
Geoff Worboys
Telesis Computing