CPU Support

[Guest D Riberdy]

We are trying to figure out how MS Windows 2003 Server counts its CPUs.

Since it only supports 4 CPUs to be used, if I have 2 CPUs with Dual Core and

Hyperthreading - what is it actually using?

 

Is it using the Dual Cores and ignoring the Hyperthreading, allowing me to

use both Physical CPUs and both cores?

 

or

 

Is it using the First CPU with both Cores and their Hyperthreaded pieces as

the 4 CPUs?

[Guest - Michel]

RE: CPU Support

 

Hi,

 

Windows first takes the physical cores before jumping to the HT (virtual)

cores.

However, if you really really really want to make sure, I recommend to

disable HT in the BIOS (in this case it won't be a loss anyway).

 

Kind regards,

Michel

 

"D Riberdy" wrote:

> We are trying to figure out how MS Windows 2003 Server counts its CPUs.

> Since it only supports 4 CPUs to be used, if I have 2 CPUs with Dual Core and

> Hyperthreading - what is it actually using?

>

> Is it using the Dual Cores and ignoring the Hyperthreading, allowing me to

> use both Physical CPUs and both cores?

>

> or

>

> Is it using the First CPU with both Cores and their Hyperthreaded pieces as

> the 4 CPUs?

[Guest D Riberdy]

RE: CPU Support

 

Is this documented anywhere?

 

"- Michel" wrote:

> Hi,

>

> Windows first takes the physical cores before jumping to the HT (virtual)

> cores.

> However, if you really really really want to make sure, I recommend to

> disable HT in the BIOS (in this case it won't be a loss anyway).

>

> Kind regards,

> Michel

>

> "D Riberdy" wrote:

>

> > We are trying to figure out how MS Windows 2003 Server counts its CPUs.

> > Since it only supports 4 CPUs to be used, if I have 2 CPUs with Dual Core and

> > Hyperthreading - what is it actually using?

> >

> > Is it using the Dual Cores and ignoring the Hyperthreading, allowing me to

> > use both Physical CPUs and both cores?

> >

> > or

> >

> > Is it using the First CPU with both Cores and their Hyperthreaded pieces as

> > the 4 CPUs?

[Guest - Michel]

RE: CPU Support

 

It has to do with the numbering of the cores in the BIOS. The BIOS counts the

physical cores first and then the virtual ones. So on a four way system, the

4 physical cores are counted and the rest (virtuals) are unused by Windows

because of the 4 cpu limit.

I found some (older?) documentation in this HP document:

 

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00257074/c00257074.pdf

 

 

 

"D Riberdy" wrote:

> Is this documented anywhere?

>

> "- Michel" wrote:

>

> > Hi,

> >

> > Windows first takes the physical cores before jumping to the HT (virtual)

> > cores.

> > However, if you really really really want to make sure, I recommend to

> > disable HT in the BIOS (in this case it won't be a loss anyway).

> >

> > Kind regards,

> > Michel

> >

> > "D Riberdy" wrote:

> >

> > > We are trying to figure out how MS Windows 2003 Server counts its CPUs.

> > > Since it only supports 4 CPUs to be used, if I have 2 CPUs with Dual Core and

> > > Hyperthreading - what is it actually using?

> > >

> > > Is it using the Dual Cores and ignoring the Hyperthreading, allowing me to

> > > use both Physical CPUs and both cores?

> > >

> > > or

> > >

> > > Is it using the First CPU with both Cores and their Hyperthreaded pieces as

> > > the 4 CPUs?

[Guest - Michel]

RE: CPU Support

 

It has to do with the numbering of the cores in the BIOS. The BIOS counts the

physical cores first and then the virtual ones. So on a four way system, the

4 physical cores are counted and the rest (virtuals) are unused.

I found some (older?) documentation in this HP document:

 

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00257074/c00257074.pdf

 

 

 

"D Riberdy" wrote:

> Is this documented anywhere?

>

> "- Michel" wrote:

>

> > Hi,

> >

> > Windows first takes the physical cores before jumping to the HT (virtual)

> > cores.

> > However, if you really really really want to make sure, I recommend to

> > disable HT in the BIOS (in this case it won't be a loss anyway).

> >

> > Kind regards,

> > Michel

> >

> > "D Riberdy" wrote:

> >

> > > We are trying to figure out how MS Windows 2003 Server counts its CPUs.

> > > Since it only supports 4 CPUs to be used, if I have 2 CPUs with Dual Core and

> > > Hyperthreading - what is it actually using?

> > >

> > > Is it using the Dual Cores and ignoring the Hyperthreading, allowing me to

> > > use both Physical CPUs and both cores?

> > >

> > > or

> > >

> > > Is it using the First CPU with both Cores and their Hyperthreaded pieces as

> > > the 4 CPUs?