I believe it has as much to do with genetics as tolerance. I can drink like a fish and don't black-out, (given I do REALLY stupid shit), but my younger brother always blacks out. I have beat his ass three times this year while he was "blacked-out." The shitty part is that you can't tell if someone is blacked-out because they just seem really wasted. He always ask: "what happened to me last night?" I tell him: "you drank too much again."
