The Corsair K90 does not include cherry mx reds under every key.
All of the programmable macro keys on the K90 and the top row (the Esc and F-keys), plus the nine keys in the center block (PrtScn, Scroll Lock, Pause/Break, Insert, Delete, Home, End, Page Up, and Page Down) use silicon dome key-switches.
There is a rather lengthy discussion on the corsair forums regarding this very subject.
If your looking for a fully mechanical gaming keyboard, you should look into the thermaltake esports meka g unit, which uses mx blacks plus has macro buttons on the side.