Came across these two studies where Mobil 1 and Amsoil were put in the same (GM LS1) engine and an oil sample taken every 1,000 miles.
Mobil 1 5W-30: http://www.brianschreurs.org/neptune.spacebears.com/cars/stories/mobil1.html#metals
Amsoil ASL 5W-30: http://www.brianschreurs.org/neptune.spacebears.com/cars/stories/amsoil.html
Mobil 1 5W-30: http://www.brianschreurs.org/neptune.spacebears.com/cars/stories/mobil1.html#metals
Amsoil ASL 5W-30: http://www.brianschreurs.org/neptune.spacebears.com/cars/stories/amsoil.html