CPU hyper threading

[Robbo]

I have played around with CPU HT in BIOS.
I disabled CPU Hyperthreading and booted into Win XP as usual. I noticed
that there is only 1 CPU recognized in Device Manager (that's logically OK).

I re-enabled the CPU HT in BIOS and returned to Windows. Now there are 2
CPUs in Device manager, however in the task manager Performance tab I can
see only one graph. When I go to View menu and CPU History I only see 1
option "One graph per CPU" and nothing else. I also found that I cannot set
afinity to processes ...
The device manager in Computer section does not say "multiprocessor" any
more...
What could go wrong?

There is definitely some issue with the Windows XP system. I checked the
LiveCD with Knoppix and it detects 2 cpu with no problem. Still, XP lists
two CPUs in the device manager, but somehow cannot use them both. The
diagnostic tool Everest shows CPU information with Hyper Threading as
"supported but disabled". It is enabled for sure in the BIOS.

What can I do to fix this problem?

 

[Edwin vMierlo]

multi posted, discussion in microsoft.public.windowsxp.help_and_support