Liquid Flow Restriction

I use a CORSAIR Hydro XD5 pump/reservoir combo unit with the pump powered by a direct SATA connection to a CORSAIR HX750 PSU and controlled by an Aquacomputer Aquaero 6 XT. There is a previously calibrated in-line flow meter and Dwyer 490 Series 1 wet-wet manometer to measure the pressure drop of the component being tested—in this case that of each radiator. Every component is connected to the manometer by the way of 13/16 mm tubing, compression fittings, and two T-fittings.


As expected, the Alphacool NexXxos HPE-30 360 sits in the bottom half when it comes to pressure drop across radiators. Interestingly, it's within error margins on the NexXxos ST25 360 and almost exactly twice that of the dual row HPE-45 360, so at least the numbers all make sense. I would classify the NexXxos HPE-30 as a low-medium restriction radiator still, especially since the only ones that can really be mentioned as high restriction units are the Black Ice Nemesis GTS and its OEM offerings that use the much thinner tubing. Ultimately, this particular radiator should not worry you much, especially compared to a typical CPU or GPU block.