A bit ignorant of hashrates. What exactly does that tell us? Volume?
Increase the power limit. It can also be because the card is getting to hot try get it cooler 7950 are real pain for example as they cant really go over 85C.
I find power limit to make mining overclocks less stable if anything. The card can go over 85c, it only matters what you have your different temperature thresholds set at it - but the lower the temperatures the better. I try not to push past 70-75c.
If it's throttling it's because it failed being stable and crashed. Adjust intensity and overclock settings down and try again.