Need Help with Hyperthreading with XP Home Edition

[js1662]

I have problem with Task manager showing only one CPU window although Device
Manager shows 2 CPUs. My system is as follows:

Motherboard: Asus P4P800 Deluxe, HT enabled in BIOS
CPU: Intel 2.8G with HT
OS: XP Home Edition with SP2

I have already updated to the latest BIOS and Intel inf. I also reset the
CMOS setting. I also did a virus scanning to the computer.

What is the possible cause to the problem? Appreciate any help!

Thanks in advance!

js1662

 

[Leythos]

I have problem with Task manager showing only one CPU window although Device
Manager shows 2 CPUs. My system is as follows:

Did you set the Task Manager to SHOW two graphs? (one graph per CPU)?

 

[js1662]

Thanks for your reply!

Under View, CPU History, it shows one graph per CPU with a dot in front so I
suppose it is already set to show two graphs. Am I right?

I saw post mentioned about the ACPI. In Device Manager, under Computer, it
only shows Advanced Configuration and Power Interface (ACPI) PC. Any clue?

js1662

 

[Leythos]

Thanks for your reply!

Under View, CPU History, it shows one graph per CPU with a dot in front so I
suppose it is already set to show two graphs. Am I right?

I saw post mentioned about the ACPI. In Device Manager, under Computer, it
only shows Advanced Configuration and Power Interface (ACPI) PC. Any clue?

That means you don't have the Multi-CPU kernel installed. If you are
brave you can try and manually install it - you would right click,
select UPDATE DRIVER, then follow through to select the "ACPI
Multiprocessor PC" (you may have to pick "Don't search. I will choose
the driver to install).

Be aware, this is not a MS Approved method.

You can also tell the Device Manager to RESCAN DEVICES for changes and
see if it does it automatically.

 

[js1662]

Thanks again. I tried but "ACPI Multiprocessor PC" is not available.
Apparently Multi-CPU Kernel is not available for XP Home Edition. It seems
like I have to upgrade to XP Pro if I have to use Hyperthreading. I have
seem conflicting information about XP Home suppose HT, even Intel's web site
said that XP Home support HT, but XP Home doesn't support Multi-CPU. It is
funny that it is supported but can't be used.

js1662

 

[Jason Tsang]

XP Home supports Hyperthreaded processors, as it is 1 physical processor,
but has 2 logical processors within it. This configuration does not require
the multiprocessor kernel.

XP Home does NOT support multiple physical processors. HT is not MP, that's
why it won't use the Multiple Processor kernel.

--
Jason Tsang - Microsoft MVP

Find out about the MS MVP Program -
http://mvp.support.microsoft.com/default.aspx

Thanks again. I tried but "ACPI Multiprocessor PC" is not available.
Apparently Multi-CPU Kernel is not available for XP Home Edition. It
seems like I have to upgrade to XP Pro if I have to use Hyperthreading. I
have seem conflicting information about XP Home suppose HT, even Intel's
web site said that XP Home support HT, but XP Home doesn't support
Multi-CPU. It is funny that it is supported but can't be used.

js1662

 

[js1662]

Thank you so much for the explanation. Hence what is wrong with Task
Manager showing only one CPU window? Should I reinstall XP Home as some
people suggested?

js1662

XP Home supports Hyperthreaded processors, as it is 1 physical processor,
but has 2 logical processors within it. This configuration does not
require the multiprocessor kernel.

XP Home does NOT support multiple physical processors. HT is not MP,
that's why it won't use the Multiple Processor kernel.

 

[Leythos]

My P4's are all hyper threaded, running XP Prof, and they all use the MP
Kernel, just the same as my Dual and Quad CPU systems.

 

[js1662]

Hi, I found the following link that suggested a workaround to re-install MP
Kernel. Should I do that for my XP Home? Will that corrupt my OS if XP
Home doesn't support MP Kernel?

http://mindfulmusings.net/weblog/2004/10/16/enable-hyperthreading-after-upgrading-motherboard/

js1662

 

[js1662]

Thanks for Mark's recommendation as given in the link in my previous post,
my PC is now normal. Computer in Device Manager now display ACPI
Multiprocessor PC and CPU Usage History of Task Manager is now displaying 2
CPU windows.

To summarize, XP Home do support Hyperthreading although it only support 1
physical CPU. To use Hyperthreading, enable HT in BIOS so that OS can
detect the CPU and install the correct HAL during OS installation. In case
the MP Kernel was not installed, you can either repair it by repair
installation of the OS again or follow the recommendation from Mark.

As many other people said, you don't need XP Pro unless you need the extra
networking and security capability that XP Home doesn't has. Of course you
will need XP Pro if you have a multi-processor motherboard running two
physical processors.

Bye!

js1662

Hi, I found the following link that suggested a workaround to re-install
MP Kernel. Should I do that for my XP Home? Will that corrupt my OS if
XP Home doesn't support MP Kernel?

http://mindfulmusings.net/weblog/2004/10/16/enable-hyperthreading-after-upgrading-motherboard/

js1662