XtremeComputing published a review on the Thermaltake Aquabay M4 HDD block

For testing all I can really do is compare temperatures as measured by the onboard sensor on the hard disk in the cooler and in the 3.5" bay. For stressing the HDD I ran PCMark 04 HDD test on loop for 1 hour, and at the same time, to raise internal case temperatures I ran Prime95 Torture test. I let the case warm up with no programs running for an hour to get idle temperatures.

ThermalTake Aquabay M4 HDD block Review