Originally posted by: Marsumane
There is something called "thermal throttling" that cards often do to protect their gpus from overheating when they get to a certain temp. Basically it downclocks the card on the fly to cool the chip. It used to happen in the 5900 series but im quite unaware if it happens within the newer cards. Possibly your card has this feature on it? Or it could be the obvious reason: that your settings changed between runs of the benchmark?