A. KB956710 is an enhancement for Hyper-V in Windows Server that increases the maximum number of logical processors from 16 to 24 and the maximum number of virtual machines (VMs) from 128 to 192. Please read the entire article on the download page as it has instructions for enabling more than 150 VMs and describes an additional hotfix you need for x86 guests if the host is using a 6-core CPU.

Once you install the update, you need to update the integration services running in the VMs by choosing the Insert Integration Services Setup Disk option under Action in the VM Connection window. The Integration Services setup will detect that an older version of the integration service is installed and prompt you to upgrade. You’ll need to restart the VM after applying the integration services update.