Audi A6 Quattro vs. FWD - snow ice climbing - uphill

Audi A6 quattro (saloon, 2.8) winter tires (vredestein snowtrac 3) and EDS. Audi A6 FWD (avant/ wagon, ) winter tires (vredestein snowtrac 3) and without EDS. \/ Audi quattro starts without a problem. Audi FWD slipping wheels and it looks like an engine speed is very high but it reaches about 1500 rpm.