Well, my computer is *very* high end, but frankly I suspect my hdd might have something to do it on. I have MnB running off a top of the line SSD disc and when I have more time, i'll install it on a regular 7200rpm WD disc and see if there's a lot of difference in lag.
Personally, I suspect that running MnB of an SSD could vastly improve performance, because that battle didn't even stress my computer.
Honestly, it's a little bit scary...I went from a 250 battlesizer with lag in hills to 1k and no lag at all...i'm tempted to tweak battlesizer to give me more than 1k but i'm afraid my computer will suddenly blow up or something, stress or no stress.