You can not feed as hard in frozen wood, because your saw will run and you will break teeth. But when you feed slower, your sawdust will be finer. So do not swage your tooth as wide as you normally would, to make for less clearance between the saw and the cut, to keep the finer dust from spilling out of the gullet. Expect some problems no matter what in the fall and spring when your wood is not frozen all the way through. The running in the cut is not all a result of sawdust spilling out of the gullet of the tooth.
Frozen wood cuts harder, loads the saw more and eventually pulls the tension out of the saw.
I have used the above system on a 5 foot Horz. The next thing I am going to try is slowing down the speed of the blade by changing the pulley on the drive motor. I would look at changing the feed rate rather than the speed of the saw. Your saw speed should be between 7,000 - 10,000 surface feet per minute. You can figure out how many teeth per minute for a given tooth space, wheel diameter and wheel RPM and figure feed rate in feet per minute.