The new Calibre P880+ OC Edition is overclocked from 575MHz to 630MHz and the memory from 1800MHz to 1960MHz. The Calibre P880 OC is overclocked from 500MHz to 560MHz and the memory of this card is clocked at 1720MHz instead of 1600MHz.
Overclocked GeForce 8800 graphics cards from other manufacturers should follow soon.