Other Multiboxing program?

I'm using KronkBoxer at the moment and I can only run 4 clients. I want to run more clients. But I can't or my intel i5 will fry itself. Some dude in Rotmg chat I came across had over 7 clients and he uses a similar intel processor, actually mine was better. What program do I use that sucks in less cpu so that I can get more clients?
And no, I do not want to code my own multiboxing program. Too much effort and I wouldn't have a clue where to begin.

Maybe his computer and/or cpu is newer or you have a lot of other processes running in the background.
Also, you can try to adjust the fps, and use the option show own projectiles if you haven't already.