Hmm. Does it stay at 30 in battles or does it drop down below that?
My initial thought is that it could be one of two things -
1) The graphics drivers being out-of-date and needing an update, or
2) The computer having multiple graphics cards (this is often the case with latops, where one weaker card is built into the motherboard, and it also has a stronger stand-alone graphics card), and it not using the "good" card to run the game.
Updating your graphics drivers in windows 8:
https://www.youtube.com/watch?v=7i8fS3Owu4E(Haven't actually watched the whole thing; just a result of some quick googling.)