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?

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?

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?