Keith Combs had setup his Lenovo ThinkPad T61p with 8GB of memory, running Windows Server 2008 and Hyper-V to test “how effectively both allocate and juggle memory.” He fired up a bunch of virtual machines. In this test, he was able to get fourteen operating system instances running at the same time. The host OS is of course Windows Server 2008 Enterprise x64 with Hyper-V RC1. In the screenshot, you’ll notice I am running six instances of Windows Vista Enterprise SP1 x64 and seven instances of Windows Vista Enterprise SP1 x86. Paging and disk I/O really went up after I fired up VM number eight.