If you mean the 3 pairs of ridges running down the sides of the 3 ramp vanes, I think they were just decorative like racing stripes (the kind on the sides of sports cars is what I mean). The "shoulder" ridges on the tops of the vanes were added in late 1964 to carry the new larger mini-baskets and to make them look more effective. They came with the new claim that the machines were now capable of washing 14 lb. loads (of mixed heavy fabrics {made with lead threads, presumably}).
Nothing in the GE family moved laundry through water more effectively than those original spiral Activators, although the 3-vaned straight Activators in the solid tubs didn't do a bad job, probably because although the solid tubs were shallower than the perforated tubs, they were wider and more conducive to rollover.