well it's somewhat like having a 333FSB vs a 400FSB, of course 400FSB would be better.
And for 64's it's all purely referred to as HTT, FSB is an obsolete term now
Doubt it'd decrease it 'significantly' but like I said it's like 333fsb vs 400fsb, that little bit always counts.
Keep in mind if you do OC the HTT past 800 then your chipset will get hotter than normal and sometimes extra NB cooling is needed.
EDIT: Note thought that that article said they threw it up to 5x for 1000MHz HTT and had no probs whatsoever so you'd probably be fine
Double Edit: Wow, after reading that article I'm surprised how well that board did. Seems like a worthy buy although I've never been a fan of gigabyte myself, maybe this will be the one to make me look twice at what they got