From the front view, with the I/O ports in the back: The Left Zone is on the left side, Right Zone is on the right side, Front Zone is the Front, and Rear Zone is the back of the system. When an overheat is detected on a card in one zone, for example the Left Zone, that zone will throttle the frequency to all cards in that zone. The fans in that zone will also ramp up to increase cooling and reduce temperature. The rest of the system remains normal, and the zone that is overheating will revert back to normal after the card's temperatures return to normal.