Like with the previous models we tested, Corsair advises us to position the fans to suck ambient air into the case. Delivering the best cooling performance, but the side effect is that all the heat is dumped inside your case.  How hot it get's inside depends if your case has cooling/vents on the top and where the PSU is positioned at. If the latter is mounted on the top, it can suck out the hot air. If it's at the bottom, as with most modern cases, the hot air will remain trapped inside. Electronics and elevated operating temperatures are never a good idea.

Time to test the more normal approach of positioning your fans. Pushing hot air out via the back and creating a more natural air flow in your case.

What we tested on the hottest of our testbeds, the i970@ 4.2Ghz, was the difference in cooling performance amongst the 3 fan profiles while reversing the flow. As you can see the performance doesn't degrade that much. From a meazzle one degree at the highest setting to just over 2°C on the lowest setting. Ofcourse results will vary depending on the airflow of your case. Our case has got two 120mm fans to suck fresh air and a mesh gril on the sidepanel. Nothing really fancy, but in some more cramped cases the differences can be more profound. But a few degrees less in cooling performance, against a lot less hot air trapped inside your cases interior is a very small compensation to make.

Pump noise wise, the Hydro 80 is at the same noise level as it's little H60 brother. While the first generation models had some gurgling sounds at startup ( mixing of fluid and trapped air ), neither the Hydro 60 nor the H80 experience this behaviour. The pump runs at a flat out 2000rpm all the time ( alike previous CoolIT models ) At least one thing we can monitor :p

But more importantly where does the H80 end up running at it's different fan profiles ? Time to give them fans a run for their money on the i970ES setup. This setup creates the highest fan speeds at idle and load, as the fan speed is related to the fluid temperature.

Running the Hydro 80 at the low or balanced setting keeps the noise at an acceptable level. Once you opt to go for maximum performance and switch to the performance preset, even the idle fan speed was at 50 dBa with the 970 CPU. The previous Hydro models didn't have this fan control build in. And were reliant to either the motherboards fan PWM or manually input in the bios ( if fan control is allowed ) It must be said that the results for the Hydro 80 are maxed out and do not reflect fan noise at a daily usage level. Ofcourse if you run your hexacore Gulftown at 4.5Ghz at 1.5Vcore you can reach them above dBa's too. Running my daily setup, based upon a much cooler 990X (at 4.5Ghz and 1.3Vcore), the Hydro 80 at the balanced preset is audible, but absolutely not disturbing, when gaming. So the above noise measurements might not reflect true operating noise.