You just have to balance out your periodics and make them efficient. I have 5 periodics triggers running every 0.05 second. Still I've yet to hear anyone complain about chunkyness in-game or anything.
I know it probably won't lag because I have about 6 - 7 periodics running at once in my TD and no one every complains about chunkiness, but it would have been nice to eliminate this one because it is going to be for an AOS with all triggered spells bascially, which could mean anywhere from 10 - 15 or even more periodics could be running at once between spells and game stuff, and that would possibly cause lag.
Actually a periodic event of 0.01 checking if multiboard is minimized, shouldn't really cause too much lag, periodic events were identified as causes of lag but I am almost sure it was because people were using conditions or actions with a lot of leaks.
I know that this won't lag, and the map probably won't, but every less periodic means a tiny less lag. I try to preserve memory as much as possible. Oh, and DaKaN, don't worry, i'm not afraid of them ;).