Fourier III (SP606B3) & Fourier IV (SP607B3-C)
The next two coolers from Spire have similar names, Fourier III and Fourier IV, and similar designs as well, so I will discuss them both together in one section.
The packaging is identical for both models, the same as the VertiCool IV package:
The same set of accessories can be found inside but the coolers are completely different:
The Fourier III and IV consist of an aluminum and copper heatsink, respectively, which hangs on four copper heat pipes going out of a copper base.
The Fourier III heatsink is designed for a 120mm fan and measures 137x126x104 millimeters. The all-copper Fourier IV (126x107x99mm) employs a 92mm fan. The manufacturer doesn’t declare the weight parameter, unfortunately. I can only say that the Fourier III is much lighter than the Fourier IV as well as than the VertiCool IV.
The plates in the coolers’ heatsinks are placed at a distance of 1.5 millimeters. There is a depression in the middle of the ribs in the dead space under the fan motor. Its purpose is unclear.
If it was made to reduce the weight of the heatsink, I doubt the reduction is substantial.
The fan is fastened on the heatsink with two wire clips in such a way that it drives air from below upwards to the heatsink ribs.
The simple and handy fastening mechanism allows to turn the fan around in the opposite direction, driving the airflow towards the CPU rather than away from it. I will test the cooler with the fan in both positions to see how this affects its performance.