So you are saying, if we had like 2 x QX9775 on a skulltrail motherboard, the Home editions won't work and you'd have to use Ultimate? I think that makes sense.
A single Q6600 on Home Premium or Basic will work and use all 4 cores, but when 2 actual processors are on the same system (as in servers and skulltrail platforms) then Ultimate is needed to utilize the extra processor.