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I had a VM with two cores. I powered it down and changed the settings to four cores.

Here's what I see:

  • System (right-click on My Computer > Properties) reports "(2 processors)"
  • Task Manager shows two CPU core graphs
  • Device manager shows four CPUs under Processors
  • VMWare reports four CPUs

It seems strange. Am I missing some step to get Windows to use the remaining two CPUs?

I'm running Windows 7 SP1 x64.

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What EXACT version of Windows are you using? – Chopper3 Mar 5 '13 at 18:35
And what Edition of which Version are you running? – joeqwerty Mar 5 '13 at 18:38
Windows 7 Professional SP1. – ashes999 Mar 5 '13 at 19:02
up vote 3 down vote accepted

You've give the VM 4 CPU's, Windows 7 will only deal with two physical CPUs, it'll see more but it's a client OS so only handles 2 at a time.

What you need to do is force it to think it's one CPU with four cores, by the way VMWare Workstation lets you define this on a per-VM basis as it's designed to Client OS based VMs, whereas ESXi is more focussed on the Server related OSs which can handle >2 physical CPUs.

Here's a hack/change to do what you need;

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This worked with a value of 4. – ashes999 Mar 5 '13 at 20:45

Most of VMware machines you will find are configured to work with the last free version of VMware Workstation, namely 6. The latter means you have 2 processors limitation. In case you have a license for VMware 6.5+ you can change "hardware compatibility" (as VMware calls it), so that you can add more processors.

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Also make sure you're explicitly setting it in esxi as 2cpu's 2cores each. that will be important as, like the previous poster indicated, windows 7 can't handle more than two cpu's.

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