What about the Sapphire, any better? Are there differences with respect to cooling?
Yeah, Sapphire cards have terrible cooling. Not as bad as XFX of course, but still insufficient. I don't know why they're always recommended for mining.
my sapphire dual-x 280x (among the cheapest cards) stays quite silent and gives solid hash rate

I may try asus direct cu top next time

GPU1 is at 4C, so the environment temperature is low. But other cards are still hot. Putting two or more case fans over the cards may help.