In the first part of this paper we will prove the Voevodsky's nilpotence conjecture for smooth cubic fourfolds and ordinary generic Gushel-Mukai fourfolds. Then, making use of noncommutative motives, we will prove the Voevodsky's nilpotence conjecture for generic Gushel-Mukai fourfolds containing a τ -plane Gr(2, 3) and for ordinary Gushel-Mukai fourfolds containing a quintic del Pezzo surface.Theorem (BMT). Let X be a smooth projective k-scheme. The conjecture V(X) is equivalent to the conjecture V nc (perf dg (X)).Here, perf dg (X) denotes the unique enhancement of the derived category of perfect complexes on X. Making use of noncommutative motives, Voevodsky's conjecture was proven for example for quadric fibrations, intersection of quadrics, linear sections of Grassmannians, etc. (see [6] and [7] for details).The first result of this paper is the proof of Voevodsky's conjecture for cubic fourfolds and ordinary generic Gushel-Mukai fourfolds. We recall that a cubic fourfold is a smooth complex hypersurface of degree 3 in P 5 , while a Gushel-Mukai fourfold is a smooth and transverse intersection of the form Cone(Gr(2, V 5 )) ∩ Q, where Q is a quadric hypersurface in P 8 .Theorem (A). Let X be a cubic fourfold or an ordinary generic Gushel-Mukai fourfold; then the conjecture V (X) holds. 3