After reading what everyone else has put, I agree, a constant fps would be better than something that fluctuates. The actual numbers are less important that the amount it varies by.
As for what i'd give up... I can't answer this question, due to the fact that I haven't experienced any fps dips yet, but mainly because I don't know how much you'd have to get rid of for a constant fps.
As for what i'd give up... I can't answer this question, due to the fact that I haven't experienced any fps dips yet, but mainly because I don't know how much you'd have to get rid of for a constant fps.