Put the X2 on me X1800XT. Unfortunately i do not have temps overclocked with stock HSF anymore. When gaming @ stock with stock HSF @ dynamic it hit around 65C at full load. This was at 65% speed which is pretty loud already imo. Now with the X2 at the same dynamic settings max ive seen so far is around 55C with the fan @ 50%, dead silent.... Pretty pleased so far !