Here are those articles I was talking about. First link is testing SLI 480's and the second link has videos of all the fan speeds of 470,480,5850,5870 - but no 5970. They do however have two 5870's in crossfire!
Real World Temperatures & Sound - GeForce GTX 480 Real World Temperatures & Sound | [H]ard|OCP Power - Temp - Sound - NVIDIA Fermi - GTX 470 - GTX 480 - GTX 480 SLI Review | [H]ard|OCP