Ok I'll check that. If I added another 6870, would I need a higher wattage unit? Maybe a 750? And would i need more cooling or would the two case fans and gpu fans be enough?
AMD recommends a 600W PSU for Crossfire 6870's, but I'd go with a good 650W unit (like that Antec), personally (for overclocking headroom, etc.).
Cooling shouldn't really be a huge problem, but more airflow never hurts.