Speedfan got a lot more functions than you might expect.
The userinterface isn't pretty but functional.
The small tools allows you to supervise the speed of your fans and if necessary to regulat them yourself. It is also able to read miscallaneus sensor data. Thus you are able to kep an eye out for the temerature and voltage of your devices.
The new version 4.34 changes many little details and new hardware is supported. A full changelog can be found here. Speedfan is available from the developers.