When tested with the fan turned around to face the mainboard, the Fourier IV and III coolers are marked in the diagrams with the word “Rev.” The red line shows the level of room temperature. Here are the results:
A few comments on the numbers. First, the Fourier coolers have a wrong fan orientation by default. The test results show that their performance improves considerably if the fan is turned around in such a way as to drive air towards the mainboard. The system fan on the side panel contributes to the overall result because the improvement is not as big on the open testbed as it is in the closed system case, but performance improves anyway.
Talking about specific models, the DiamondCool is a weak and noisy device with low cooling performance. The VertiCool IV and both Fourier are mediocre models as even at their maximum speed they cannot compete with the Cooler Master which costs half the money. I don’t even compare them with the Thermaltake Big Typhoon which didn’t think much of both the four overclocked cores and the summer heat.