Hyperthreading and XP

[Guest]

I currently have a dual XEON machine runing XP.
It has HT turned on and clearly shows 4 CPUS..OK

We are getting a lab of HT Pentium 4s.
- Will I get HT with them? I have been told not.
- If so do I need to create an image on those HT machines to get HT or can I
use an image created on non HT P4 (eg 2.8Ghx)?
- I know that you turn HT on in BIOS so I would have thought that XP just
sees 1 or 2 CPUs at the BIOS level with a single CPU HT machine. Given that
XP is licensed normally for up to 4 CPUs then all is OK???

Thx
--
David Jones
Senior Lecturer
School of Electrical & Computer Engineering
RMIT University
+61 3 99255318

 

[Carl]

I belive you only get hyperthreading is if you buy the intel processor which
supports it.800FSB

 

[Zack]

Hi,

As I've not had experience with your particular issue, I
won't answer your questions specifically. But as I have
only recently set up my own HT P4 on XP, I can tell you a
few things that I've found.

XP successfully recognized my HT P4, but only after I
performed a "repair" operation over my original
installation of XP. It has worked just fine ever since.
XP does recognize that the system is working with 2 CPUs,
and so I suppose that you would be right - it most likely
gets this information automatically from the BIOS.

Given my own experience, I would predict that you will
need to create a new install, then use images of that on
each of the lab's computers, or risk unrecognized hardware
issues with the old images. I had no problem using
Windows XP with what it saw was 2 CPUs, and so I don't see
any reason that you would have a licensing issue.

I hope you can find some useful information in my post, at
least until the gurus come back .

 

[Guest]

Thanks, most useful.

Hi,

As I've not had experience with your particular issue, I
won't answer your questions specifically. But as I have
only recently set up my own HT P4 on XP, I can tell you a
few things that I've found.

XP successfully recognized my HT P4, but only after I
performed a "repair" operation over my original
installation of XP. It has worked just fine ever since.
XP does recognize that the system is working with 2 CPUs,
and so I suppose that you would be right - it most likely
gets this information automatically from the BIOS.

Given my own experience, I would predict that you will
need to create a new install, then use images of that on
each of the lab's computers, or risk unrecognized hardware
issues with the old images. I had no problem using
Windows XP with what it saw was 2 CPUs, and so I don't see
any reason that you would have a licensing issue.

I hope you can find some useful information in my post, at
least until the gurus come back .

 

[Guest]

Yep, P4 3.2 HT

I belive you only get hyperthreading is if you buy the intel processor which
supports it.800FSB

 

[Nathan McNulty]

See my inline comments

----
Nathan McNulty

I currently have a dual XEON machine runing XP.
It has HT turned on and clearly shows 4 CPUS..OK

We are getting a lab of HT Pentium 4s.
- Will I get HT with them? I have been told not.

Some Pentium 4 Processors do not come with Hyperthreading. If you have
been told the ones you are going to recieve do not have Hyperthreading,
there is no way to get it without buying processors that have this
feature. Both Pentium 4 C and E revisions have HT. These both also run
at 800 MHz on the Front Side Bus.

- If so do I need to create an image on those HT machines to get HT or can I
use an image created on non HT P4 (eg 2.8Ghx)?

When you are creating an image, the hardware differences must be
exttremely minimal. You will not be able to use an image from the XEON
setup since the motherboard/CPU's are so different. The best idea is
going to be to image one of the new computers with HT and use that on
all the others assuming they are all the same.

- I know that you turn HT on in BIOS so I would have thought that XP just
sees 1 or 2 CPUs at the BIOS level with a single CPU HT machine. Given that
XP is licensed normally for up to 4 CPUs then all is OK???

Hyperthreading is usually enabled through the BIOS. It isn't so much
that Windows obtains the information from the BIOS, but that it gathers
the information from the hardware which is controlled by the BIOS. If
you enable HT in the BIOS, it then tells the motherboard to allow the
CPU to use this feature. Windows detects this change and updates itself
accordingly.

 

[Guest]

Thanks Nathan again. My understandings on this issue have been confirmed.

 

[Paul]

No, on 533 fsb motherboards, it needs at least a 3.0ghz
533 fsb CPU, so it gets enabled in the BIOS.

On 800 fsb motherboards, you need a 2.4 ghz 800 fsb CPU
to enable HT in the BIOS. If you get anything under a 800 fsb
mobo/CPU, or 533 fsb CPU/motherboard HT wont work.

Even if you image a system that has HT enabled.