Wrong number of CPUs appears in task manager and system information

[Rui Vilao]

Greetings,

We have installed Windows 2000 Advanced Server with SP3 on a Proliant DL580
with 4 CPUs.

Everything is working OK... However in task manager and system information
the server shows 8 CPUs...

Any help/suggestion is highly appreciated.

Thanks in advance for your help,

Kind Regards,

Rui.

[Jeffrey Yadzinski_1 · Accepted solution]

I have seen this problem on other G3 servers as well. We have a DL380 G3 with Dual 2GHz procs and it shows up as having 4 procs. Is this because of multithreading the processors? I am using Windows 2000 Server. Thanks

Jeff

[Bryce Dennison]

Hello,

We recently installed a Proliant ML370 G3 with Windows 2000 SP2.

We have 2 2.8GHz processors, but Task Manager, Performance Monitor, and System Information show 4.

Also SI shows the 4 procs running at nearly 38000MHz!

Everthing seems to be working fine here as well, but we would like to get to the bottom of this.

Thanks in advance for any assistance,

Bryce Dennison

[Bryce Dennison]

Hi,

I think I found the answer further down in the forum:

"May 26, 2003 10:32 AM GMT

--------------------------------------------------------------------------------
Please check the following links to know more about the Hyperthreading:

As per Intel, W2K does not (yet) support Hyperthreading, i.e. W2K does not know that the extra processors are not "real". Intel recommends disabling Hyperthreading when using W2K. So far, only Win XP supports Hyperthreading:

http://www.intel.com/support/platform/ht/os.htm

This one is from Microsoft:
http://www.microsoft.com/windows2000/docs/hyperthreading.doc"

I'll try this later today and let you know.

Bryce Dennison.

[Sunil Jerath]

Hello Folks,
This can be corrected by going in the BIOS settings. Under the Advanced features just highlight the Hyperthreading and then select disable. This will show the correct No of CPUs.

Regards,

[Jens Baumann_2]

Just some further information. If you disable hyperthreading then, yes, the CPU number will show correctly and task manager etc. will show the correct number of graphs. But you will also lose performance, since hyperthreading gives you, depending on the applications running, another 10-20% of performance. The newer Intel CPUs ARE in fact "two processors in one", but they share cache etc., so it is not the same as having two physically separate processors. Still, Windows correctly "sees" two processors per hyperthreading CPU. So, if you disable hyperthreading, you effectively disable performance you paid for. The only point which speaks FOR disabling hyperthreading is, as posted above, that Windows 2000 does not officially support hyperthreading, and some here have had problems (crashes) they could fix by disabling it. Windows 2003 should work fine with hyperthreading activated.

[William Petko]

All versions of the Windows 2000 operating system are fully compliant with HT and should run without error on HT-enabled systems. However, neither Windows 2000 nor any of its service packs support the identification of HT processors. The type of modifications that are required for HT processor identification and support are not typically supported in a service pack. There are no plans to introduce this support in any future Windows 2000 service pack.

Since the release of Windows 2000, it has supported HT. Now there are two different levels of HT support (mainly for licensing).

Hyper-Threading-Aware - Can distinguish between a logical and physical processor

Not Hyper-Threading-Aware - Can not distinguish between a logical and physical processor.


Also the link from Intel that states you should disable HT is for the Pent 4 processors on Desktop systems not the Pent 4 Xeon Processors you find in Servers. The reason for this is on the Pent 4 processors HT is only supported on 3ghz systems and above and if you have it enabled on a 2.8ghz system you could run into problems because the hardware does not support it.


http://www.microsoft.com/whdc/hwdev/platform/proc/ht-windows.mspx

http://www.microsoft.com/windows2000/server/evaluation/performance/reports/hyperthread.asp

http://www.intel.com/eBusiness/products/server/processor/xeon/wp020901_sum.htm?iid=ipp_srvr_proc_xeon+prodi_ht&