I get nb temps of around 45-49 degrees on my Gigabyte GA X58A UD7 mobo . The UD7 at the time of buying being the flagship motherboard of gigabyte came with hybrid silent pipe cooling . I guess is it that keeping the temperature lower in my case .

Hybrid Silent-Pipe module is an additional heatsink unit that attaches to the water-block northbridge cooler in order to maximize air cooling.
I have some pictures of it