Elite Bastards posted a review on the XFX Radeon HD 5770 XXX 1GB / Sapphire Radeon HD 5770 Vapor-X 1GB

While XFX have kept their eyes firmly on clock speeds and performance, Sapphire's Radeon HD 5770 Vapor-X board sees only a token 10MHz core clock speed increase in this discipline to mark it out from the pack. Instead, the real highlight of this particular part is the presence of Sapphire's custom-built vapour chamber cooling solution, as you can see below.

This dual-slot Vapor-X cooler differs from a reference cooling solution not just in the way it works, but also in size, utilising a larger fan but not covering the entire front of the board like AMD's own offering. The only real downside of this design is that it renders it unable to effectively exhaust hot air out of the rear of the chassis like a reference part.

XFX Radeon HD 5770 XXX 1GB / Sapphire Radeon HD 5770 Vapor-X 1GB Review