GTX 480 Watercooled by EVGA

GTX 480 Watercooled by EVGA. I am wondering how big have to be a radiator to cool this HOT GPU but still w8ting for some youtube rewievs by trubitrar.
Cards are overclocked and the clocks are:

EVGA GeForce GTX 480 FTW Hydro Copper (015-P3-1489-AR): 750 / 1500 / 950 MHz,
EVGA GeForce GTX 470 FTW Hydro Copper (012-P3-1479-AR): 650 / 1300 / 950 MHz,

There Are also stock cooled overclocked cards but they are not as fast as this watercooled monsters.