Dell Precision M6500 Windows Server 2008 R2 w/SP1 VM performance issue with Hyper-V Role enabled

I have had the extreme pleasure of using one of Microsoft’s Dell Precision M6500 Mobile Workstation for TechDays 2009, TechDays 2010 and now for the upcoming Ottawa CodeCamp (Ottawa IT Day for the IT Pro).

I have had the machine a few weeks now and had plenty of time to spend with this machine….initially this was not so good due to the VM performance.  I went to the Dell support site and updated everything including the BIOS but did not have any effect.

The machine is configured as follows:

• Intel Core i7 (x 920) 2.0GHz (4 cores with Hyper Threading Enabled)
• 16GB RAM
• 256 GB SSD (location to run VMs)
• 256 GB HDD (OS and ISOs)

One of the issue I noticed with the VMs in my demos was the CPU was VERY BUSY doing something all of the time (This really sucks during a SharePoint 2010 session I can tell you)

You can see above that if the “Time Synchronization” service is enabled for the virtual machine the system event log is being updated every 10s with a “The system time has changed to…”

Initially my WORKAROUND was to disable the “Time Synchronization” offered by the Integration Services but then the VM time was completely out of wack…this is not great if you are running a DC as a VM and expect Kerberos to work properly.

I did some more searching and did experience a few BSOD on the machine, so I did some searching in the Microsoft support forums on Intel i7 hotfixes/workarounds.  I had come across KB 975530  but it didn’t really 100% related to my issue.  I knew that is was Power Saving related but the Dell BIOS doesn’t allow you to change very much.

I thought I would try the workaround (Registry Change) and reboot, you can see below that the CPU is very calm and performance is snappy as one would expect on a machine like this.

These are the steps I followed as per the KB:

Disable the Advance Configuration and Power Interface (ACPI) C-states by using a BIOS firmware option on the computer. If the firmware does not include this option, a software workaround is available. You can disable the ACPI C2-state and C3-state by setting a registry key. To do this, follow these steps:

1. At a command prompt, run the following command:

   reg add HKLM\System\CurrentControlSet\Control\Processor /v Capabilities /t REG_DWORD /d 0x0007e066

2. Restart the computer.

Hopefully this post can help someone else who is using of of these awesome Dell Precision M6500 machines for Demonstration or Development purposes.