I prefer test certain things on a virtual machine before install them on the main computer, so I created a Fusion 8.0 virtual machine for Yosemite. Not only the Yosemite VM runs very slow, but also has a rather low resolution desktop. In the mean time, Windows 10 VM runs as great as that on the MacBook (13" Early 2015) and in high resolution. What did I do wrong? Does OSX virtual machine always run slow and in low resolution?