Both play some of the same artists, Octane is like Top 40, current chart busters, where Turbo is older stuff, from the 90's and 2000's. Disturbed, Rage Against The Machine, NIN, Staind, Godsmack, KoRn, Linkin Park, Tool, Deftones, Limp Bizkit are among the acts you'll hear from on Turbo, but mostly their older stuff.
Octane is newer stuff, kinda like "top 40 hits" rock stations, only MUCH different content. You'll hear stuff that would NEVER land on a regular radio station. Five Finger Death Punch, Disturbed, Avenged Sevenfold, KoRn, Seether, Shinedown, Metallica, Godsmack, Linkin Park, Volbeat, Chevelle