As the only manufacturer in the world, Alphacool is uncompromising in its choice of materials and exclusively uses copper for all water-carrying parts in the radiator. The header tanks, cooling fins, and cooling channels are made of pure copper. Only the connection threads are made of brass, and the outer casing of the radiator is made of steel sheet, which consists of different materials. HPE = High Performance. The HPE radiators are based on the NexXxoS series. But what’s new? The HPE variant features additional cooling channels and a very high fin density. Due to its technical design, the cooling performance significantly increases without restrictively affecting the water flow within the radiator. When equipped with fans on both sides in a push/pull configuration, a noticeable reduction in water temperature compared to standard radiators is achievable. X-Flow instead of U-Flow. In traditional PC radiators, the water flows in a U-shape, meaning the water inlet and outlet.