hello Richard,

> If the machine has only 1 physical CPU then
> the multi CPU kernal of WinXP/2000 will fail
> to work correctly when HT is off in the BIOS.

I supposed this, then I have turned HT on again.

> I would recommend turning off Seti@home until
> the machine is running okay

To be honest, even with the Seti client running and using 51% of cpu,
the machine is still brilliant. Then, with CPUAffinity = 1 also FB is
running smoothly and very fine. No problems at all until now.

> What OS is the older P4 2Ghz running?

The same, Windows 2000 Pro SP4, and also on this machine there is a
Seti client running happily with 100% of cpu usage, there is no HT on
this mainboard (Asus P4B533 512 MB ram).

> Have you tried FB on that?

Of course :-) This was my old machine and there is still FB installed
and running happily :-)

I have also to say that I have the same conditions on my notebook as
well. It's an Acer 634 LC with a Pentium 4 Mobile 1.8 and 512 MB of
ram with Windows 2000 SP4, FB installed and a Seti client working with
100% of cpu usage. Even here all is smooth and fine.

But to finish this thread (now slightly off topic :-), all my doubt
came from the fact that on the newest machine, turning HT off makes it
almost unusable. I think that the answer is that if the mainboard
supports HT, Windows loads the HT kernel even if it is disabled, as
Martin said, and being in this situation, performance becomes very
poor. On the other machines, I suppose, the HT kernel is not loaded,
and that's why they run fine even with 100% cpu usage (maybe :-).

I was only wondering what could happen if I set CPUAffinity = 3, to
use also the virtual cpu. I haven't understood well if Firebird 1.5
RC8 can use it, but for sure the machine will become unusable.

And what about setting CPUAffinity = 2, so FB uses the other cpu that
is not used by the Seti client? Mmmmhhhh...

Regards
Salvatore