It is definitely a temperature issue. I have the mobility 5450 and the same happens to me, when im running wow my temps are 50+ which is way to high for wow, but tbh I am yet to find a solution outside of sticking a fan infront of the vents for my laptop. I would love any possible solutions because its really annoying in raids and is too costly in arena i've been playing on my crappy desktop to avoid gamebreaking pauses.