Top notch. These are the Races and even these have plenty of power. Haven't felt any fade yet (but the longest runs i've done are 2mins) but i'm pretty sure they would be fine for even an alpine decent. Honestly, the best brakes i have ever used.
I'd say they are easily more powerful then my old Elixir CR's, and they were pretty much the go-to brake for downhill rigs a couple of years back... So yeah, you should be good!