Tracks that have every window clipped allow you to use extrovert drivers (which drive off the rubber lugs the same as regular drivers do, but also drive on the track windows), which greatly reduces ratcheting, allowing you to run your track looser, so there is less friction and more track h.p. The downside to every window clipped is that they are heavier than every third window clipped tracks. If you don't plan on running extrovert drivers i recommend every third clipped for their lighter weight.