In air cooling the radiator is effectively stuck to the cpu, this limits it's size, however it has the advantage of very efficient heat transfer using heat pipes because it's right next to the cpu.

Water cooling big advantage is that you can move the radiator away from the cpu and therefore have a bigger radiator in a place with better air flow. However water isn't as efficient a heat transfer device as the heat pipes used in air cooling - so you need big pipes n pumps and lots of flow to make up for that.

These coolers seem to take the worst parts of both solutions - they attach the radiator to the cpu limiting it's size, and use water as the heat transfer method but with low flow due to small pipes n pumps meaning it won't work as effectively as standard air cooling heat pipes.

any cooler that can't outperform a $30 freezer 7 pro doesn't even need to see the light of day.

The coolant in the Revo is almost certainly ammonia, which also explains its all-aluminium design (as copper dissolves in ammonia). You can also tell that it's a thermosiphon rather than a heatpipe cooler because of the fact that it's sensitive to orientation. One would not expect a thermosiphon to work better than a heatpipe under small temperature differences, and indeed your results show that it doesn't. The other coolers most likely failed to offer acceptable performance due to their weak pumps.

nice cooling test...
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