Slow responding console view in Esxi 5.1

Hi,

I am using Esxi5.1 and vsphere client 5.1.0 to run 5 VM's (Win2k8r2 x64), each allocated 8GB Ram, 128MB Video Ram, 2 virtual CPU's. If I try to switch between the VMs and use the console view tab, the embedded window hangs ona black screen for 30 seconds and then displays the VM. While working within the VM the speed is fine but for initial viewing and switching between them I have this problem.

I am not using windows credentials to log in, I have tried turning off Automatic Root Certificate Updates, and checked that the VGA drivers are installed.