I'm still testing, and that 1Ghz may not be a total stable OC, but I've been playing games and it hasn't crashed on me yet.
The fan on GB-OC is not load at all. You can hear it at top-speed 75%, but it's pretty quiet to be a GPU-fan.

The SOC-BIOS I found says: Voltage: by ASIC (0.9625 V - 1.0500 V) tho. I don't know how they are going to get it up to 1GHz. Maybe they got better a chips? We have to wait and see.