There are different types of Virtualization. Type 1 Hypervisor and Type 2,
Type 2 are the most commonly used like VirtualBox and VM Ware, where you run an OS inside an OS.
Type 1 for example KMS and QEMU are different, because they have more access to the Hardware inside your System. They usually can use the Hardware to its full potential.
Do some research if you are interested in it.
In regards to what @Spanch001 said, EAC probably looks for Strings inside your System information that include something that is linked VirtualBox or VM Ware. You can actually spoof it using the registry.