Hyper-V in 8.1 and 2012R2: what's the difference?

Question

Virtualization

I choose OS for i7 with 16 GB of RAM. The number of simultaneously working virtual machines - up to 5, probably.
Questions
1. Does 8.1 have any restrictions on this?
2. Are there any performance and behavior differences between 8.1 installed as a hyper-v host compared to 8.1 being a hyper-v guest (2nd generation) on a 2012R2 host.
3. The second question is related to the fact that sometimes you want to get maximum performance from one OS. The script is supposed to be " Shut down all virtual machines on the 8.1 host and use 8.1 for normal desktop purposes with maximum performance ", or " On the hyper-v server 2012R2 host, mute all virtual machines, except for one 8.1, which will give the maximum amount of resources". Which scenario will provide the best performance?

Answer 1

Licensing. Not? =) I mean that the client part is required for the eight. And that hypervisor is completely free. Innovations to experience. Google.