Thanks, that confirms my calculation.
Right now, I have 65 idle 2vCPU virtual desktops on one of the hosts. The virtual desktops are all powered on and running Windows 7. Each virtual machine is using 20 to 40Mhz just powered on and with no one logged on, which is not too much. However, if you look at CPU Ready % for the host, it is at 15%. This means before any user even logs on, I am already seeing higher CPU Ready % than the article recommends (<10%)!
Of course, if I power down all the VMs and run only a couple, the CPU Ready will likely go way down. However, if it is true that users will see slowness past 10% CPU Ready then we will be lucky if we can fit 30 users on the four processor server before they start complaining.
We are going to try a few more things tonight, like switching to 1vCPU VMs instead of 2 vCPU. If anyone has some other tips/advice, feel free to add.