pretty sure my 580 with ek block is single slot but you don't want watercooling, generly fast and single slot air = really hot like the GTX 460 will be i could imagin
I don't remember what they said about noise though. It's also longer than a typical GTX460.
EDIT: Here's Guru3Ds review
Edited by sLowEnd - 1/16/11 at 2:06pm