Exchange 2007 hardware requirements query

Hi

I have been reading the hardware requirements for Exchange 2007, and am confused about a couple of things -

a) The requirements quantify CPU's in terms of "processor core" - does this mean that a quad-core CPU is counted as four cores, a dual-core as two cores etc?

b) There seem to be two ways to calculate memory requirements for the MBX server role, the User profile - where, for instance, the recommendation for a heavy user is 2GB + 5MB/mailbox, and also by Storage Groups, again, for instance, 9 SG's require 5GB memory.

Do we add these two figures together, or take the higher value?

c) The maximum processor core recommendation for the MBX server is "8 x processor core with 4 x being the optimal configuration", and the minimum is "1 x processor core with 2 processor core recommended".

Does this effectively mean that the RECOMMENDED value is 4 processor cores (for the best configuration), and the minimum recommended is 2 processor cores?

Surely, for 8 cores would be better than 4?

Many thanks in advance