All VM's are totally dependant on the resources (memory, disk, processors) of the host operating system, and how much of these resources have been allocated. Presumably you are using VirtualBox to run the VM instance? Try increasing the amount of memory allocated and add another processor from the default settings used when the appliance was imported. This should make the VM run faster, but it will impact the host system.
Screen-shot of what I'm talking about (in the MacOS version of VirtualBox) attached.
Pega Academy VM's are for education and learning purposes, they are not designed to run and perform like a tuned, performance monitored Pega environments.