Proxmox Hypervisor, vCPU, RAM... etc

[techlists at phpcoderusa.com]

Hi,

I just watched a video that covered the Proxmox Hypervisor.  Seems 
simple enough.  I've used Oracle's VirtualBox for years.

So I did some research on what a vCPU is.  I was suppressed.  The math 
given was (Threads x Cores) x Physical CPU = Number vCPU.

I have an old laptop that has 1 socket, 2 cores, four threads, and 4GB 
of RAM.

Given the math (4 x 2) x 1 = 8 vCPUS.  Is this correct?

 From my reading it appears that RAM is not shared, so my bottleneck is 
RAM not cores or threads.

I am a PHP developer and a local vps would need 2GB of RAM at a minimum. 
  I have found a LAMP VPS will crash if allocated less than 2GB of RAM, 
and will run will on 1 vCPU.

The good news is I really only need one VPS to be active at any given 
time.

If I wanted to build a box that could run more than one VPS at a time, 
lets say 4, and I wanted to allocate 2 vCPUs and 4GB of RAM I would need 
4 threads x 2 cores to run the 4 VPS configured with 2 vCPUs each.

What about RAM.  Looks like I would need a minimum of 16GB of ram.

How much resources does the Hypervisor need, in this case Proxmox?

Thanks!!
Keith