There is a good link in this thread to one of the test. I have also seen test on TireRack.com
http://www.xoutpost.com/bmw-sav-foru...ad-winter.html
Performance winter tires are designed for light snow as well as dry and wet traction in colder, winter temps. Snow and ice are designed for, well, heavier snow and ice. There are now different catagories of tires to be used in the cold and snow. Just pointing out that there are different tires for differnt uses in winter now a days.