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Disabled Hyperthreading and Device Manager now only shows 2 of 4 processors

 
Dave Holtz
Occasional Advisor

Disabled Hyperthreading and Device Manager now only shows 2 of 4 processors

We disabled hyperthreading today on a DL580 G2 running Windows Server 2003 and now Device Manager only dispalys 2 of 4 physical processors. Task Manager correctly displys 4 processors and perfmon also displays 4. How can we get Device Manager to correctly display 4 processors without having to reinstall the OS?
3 REPLIES
Ivan Ferreira
Honored Contributor

Re: Disabled Hyperthreading and Device Manager now only shows 2 of 4 processors

How many real physical processors do you have? Remeber that with hypertheading enabled, you double the ammount of processors displayed. So, if you disabled that, I'm not sure about what is reporting right, device manager or task manager.
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
Dave Holtz
Occasional Advisor

Re: Disabled Hyperthreading and Device Manager now only shows 2 of 4 processors

I have 4 physical processors and only Device Manager is reporting 2.

Thanks, Dave
Matthijs Wijers_1
Trusted Contributor

Re: Disabled Hyperthreading and Device Manager now only shows 2 of 4 processors

Device Manager reads the CPU information from the registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\GenuineIntel_-_x86_Family_15_Model_\_0

0 refers to the first CPU in the computer. In a multiprocessor system, 1 refers to the second physical CPU or to the second logical CPU in a multiple logical core processor system

More information:
"Different ways to determine CPU speed in Windows XP or in Windows Server 2003"
http://support.microsoft.com/kb/888282/EN-US/

You do run the ACPI_HAL?

Regards,
Matthijs