OCC has published a review on the Sapphire HD 5870 and HD 5750 Vapor-X

After looking at many of Sapphire's Vapor-X lineup, I have to say that the Vapor-X lineup delivers the goods, in terms of performance and cooling, with the overhead available to increase the level of graphics performance without fear of overheating the video card. In the past, ATI cards were notoriously hot running, but not anymore. The Microloops Vapor Chamber Technology does what it is supposed to do, keep the components cool! At stock or overclocked speeds, the cards never went above 60 degrees Celsius!

Sapphire HD 5870 and HD 5750 Vapor-X Review