Motherboard temperature reaches 124° C?

The sensor is not necessarily broken, the software could do bad interpretation of its data.

Check the temperatures with SpeedFan.

Before you take the motherboard back to the shop due to Speccy not recognizing the correct temperature, let me add my two cents.

I have the exact same problem, the exact same temperature, even though my CPU and graphics card are running about at about 36C because I went overboard with case fans.

However, and this is what I feel may be relevant, I also have the exact same motherboard as you. Now, do we both have versions that function perfectly otherwise but where the MB temp sensor is broken, or could there be a problem with how this particular motherboard talks with Speccy?