Windows Server 2008 failed to load 2 CPU's

[aldav]

I'm running WS 2008 Enterpise Edition SP1 in a virtual machine. I'm using VMWare ESXi 3.5 Server. The hardware I'm running in is the following:

Manufacturer: HP

Model: ProLiant ML350 G5

Processors: 2 CPU x 2 GHz(dual core)

Processor Type: Intel® Xeon® CPU 5160 @ 2.00GHz

Hyperthreading: Inactive

Total Memory: 6.00 GB

 

I had WS 2008 installed in the PC and it found 4 CPU, one for each core.

The problem is VMWare is providing 4 virtual "physical CPU's", not logical, and Windows is showing 4 CPU's in the device manager, but only 2 in the task manager. The environment variable NUMBER_OF_PROCESSORS is set to 2. Is there any limitation in Windows Server 2008, limiting the use to only 2 physical CPU's? I post this problem in VMWare community forums and they told me it seemed like a windows problem. any clues?

[F2 Staff]

There is no limitation. It has to be a vmware problem.

[aldav]

There is no limitation. It has to be a vmware problem.

 

Yes, I though so. Still, the guys at VMWare forum said something that was true. Windows is seeing 4 CPUs in the device manager, so, VMWare is providing 4 virtual CPU's. The problem is that Windows is only using 2 of those CPU's, showing only 2 in the task manager. Therefore, something's wrong in the way Windows is seeing those CPU's. I'm running WS 2008 on top of ESXi 3.5 Server. Any clues?

[F2 Staff]

I don't think hyperthreading is supported in a virtual machine so it will only see the 2 logical cpu's.

[aldav]

Well, at some point you're right, hyperthreading is not supported. Nevertheless, it doesn't matter, because my hardware contains 2 Dual Core Xeon CPU's. ESXi can see the dual cores, so, eventhough I have 2 physical CPU's, I have 4 logical CPU's. ESXi transforms each "real" logical CPU into a virtual "physical" CPU, providing each virtual machine with as much as 4 vCPU. Again, these vCPU's are treated as "physical", not "logical".

That's why I don't understand why I'm only seeing/using 2 CPU's in my virtual WS 2008 Enterprise SP1, even though I provided 4 vCPU's and the virtual OS is seeing 4 vCPU's in the device manager.

Any ideas?