Hyper-V 2008 and processor allocation

[Sanm2009]

How many processors can be allocated to one Vm from Hyper-V manager. The host will have 2 x 6 Core CPUs. Is there a limit imposed my windows server and do same limits apply to server 2008 and 2012?

[clodhopper]

I read a little while back that M$ advice this

 

As a general Rule with HyperV allow 4 Virtual processor (VP’s) per physical / logical processor (LP’s) with a max of 8 VPs / LP

 

So you should be able to allocate 48 cores in total or 96 if low usage machines.

 

Personally I stick to the 4 to 1 ratio :-)