Any one played around with type one hypervisor booting multiple OS , what is the performance hit ( it has to be lower, right ? As compared to native boot)

I'm confused a bit.

Booting multiple OS... Do you mean multiple OS as in several VMs?

In simple terms:

Tier 1 is low level - the server starts directly into the hypervisor, which is usually a most minimal runtime (e.g. in KVM the Linux kernel) and provides direct access to the hardware for the VM.

Tier 2 is just the distinction that the Hypervisor runs software based in the OS. Easiest example is Virtualbox.

Nowadays (or more like 10+ years) the distinction between Tier 1 and Tier 2 is really blurry to non existent for most hypervisors.

E.g. Virtualbox provides hardware passthrough and uses not only the user space, but kernel for hardware supported virtualization - yes it runs in an OS, but it's not entirely different from Hyper V / KVM.

Proxmox e.g. is a Debian based virtualization solution running KVM, KVM allows pass through and all kinky shit of Qemu, which is really awesome. I wouldn't see it as Tier 2 just because it is a software running as an OS - that's what I mean by blurry or non existent...

i think 2005 and earlier the distinction between type 2 and type 1 was more relevant... Brain says somewhere between 2005 and 2010 started the HW virtualization hype with X86 CPU extensions and all the glory.

I have seen some videos with booting multiple type 1 VMs and running windows and macos on same system, so i was thinking if there is any performance hit

https://youtu.be/lztH7BUxIoM