Priced 40 percent less than the NH-U9DX i4, the R27 still only reaches a value point of one percent below the average of all four coolers. The best 3U cooler in today’s test, noise concerns prevent us from recommending the R27 to PC users. The R27’s fan ignored the PWM signal whenever the CPU got slightly warm, and kicked the motor up to full speed. Most users can tolerate a 49db fan for no more than a few minutes, and persistent rather than peak noise forces us to again call this a server room part.
The NH-U9DX i4 is the clear winner in value, noise and cooling power, approaching its non-Narrow ILM sibling in all three areas. Problem spots include a five-inch height that slightly exceeds 3U limits, and 32mm to 35mm of maximum clearance for the nearest DIMM. Because its performance level is so much higher than those of the two preceding parts, we recommend that builders select their DRAM and cases around this cooler rather than get stuck with a hotter, noisier machine.