Most quad cores these days are simply two dual cores stuck together.

SLI will probably be a problem still - the drivers *sigh* still are not very good.

If you horizontal span or play on a single HUGE (think 24 or 30" screen) you will have FAR better fps than if you play on dual view, which is practically unplayable with 5 open WoWs, even on 8800GTXs.