If you compare Noctua NH-D15 with any of the high end liquid coolers (closed loop), you’ll not find something better than Noctua NH-D15 as it’s one of those products which deliver great cooling performance while working quietly. If you still want to look for others, you can check the following CPU Coolers: Corsair H100i GTX NZXT Kraken X61 Thermaltake Water 3.0 Extreme S DEEPCOOL Captain 240M CM Nepton 240M