Scott Drummonds created the following post:
My colleague in product management, Praveen Kannan, has been working to extend Perfmon to show some ESX performance counters. This capability is automatically installed with VMware Tools on vSphere 4. But Praveen and I have made a stand-alone version available to those of you that are still on VI3. Download it here to give it a try.
To install, place the file in an appropriately-named directory on any Windows VM on VI3. Double-click the executable, which will self-extract the files into the same directory. Run "install.bat" and you’re done.
Once you bring up Perfmon you’ll see two new performance objects on your computer: "VM Memory" and "VM Processor". These objects contain counters exposed by ESX that accurately reflect the VM’s memory and CPU usage. Here’s Perfmon on my test VM after I’ve installed the tool.
click here for more info.
ICT-Freak.nl 
Thanks for the tip !