David Hume wrote that personal incredulity is not proof. Have you gone back to your old wheels and find that the speed returns? You might have to do a few days back to back, switching each day, to establish that the new wheels ARE slower, and that you're not simply noticing some unrelated condition like wind or tire pressure and blaming it on the wheels. If the new wheels are slower, I would tend to blame it on the higher spoke count, lack of aero spokes, and higher weight, rather than on cartridge bearings. If cartridge bearings were slower, no racers would use them, as opposed to ALL racers.