I run 32mm pirelli cinturatos on my winter bike. While I am slower in the winter, it's not strictly down to just tyres. Bike geometry, weather, and road conditions all play a part in it (moreso than tyre IMHO). I have a 16 mile commute, and it adds around 5 minutes to my commute time over my summer bike. Some of it is also due to my winter bike just doesn't have the same feel as my summer bike (CX vs aero), so it's not as fun to ride (on the road. trails and gravel it's great fun).