Well, when you talk to those super computer guy, the current stuff on the market is never gonna be good enough.
Does the current corp of dual core mobo works with dual core? absolutely. Do they fully use the capability? well there will always be room for improvement.
I'd say single core mobo probably is ahead of dual core mobo in terms of architecture that takes full advantage of the CPU. When I say that, I mean not just able to run the cpu, but have an efficient architecture to pass the info from cpu to memory, pci/pci-e card, and all other components and vice versa. I say that because mobo/chipset maker have years to work on single core, and the logic is easier to handle than the dual core, just like on the software side.
With 2 cores availabe to the motherboard, I am sure there are more efficient algorithm or logic out there that chipset maker can put into their current product to run the dual core more efficiently, for example passing info to memory faster and handle/queuing multiple request from each core better.
So I think what the guy said makes sense, if you don't just look from the point of view if the mobo can run the CPU at 100% utlization, but if it is able to process all kinds things passed to subsystems on the mobo efficiently.