Fan Speed Management
The PSU is equipped with a 140x140x25mm Yate Loon D14BH-12 fan. Notwithstanding the huge wattage of the NRP-HC1501, it does not have auxiliary fans.
This is an ordinary 7-blade fan with ball bearings. According to Yate Loon, its rated speed is 2800rpm.
The fan speed is constant at 1000rpm until a load of 600W. The PSU is not quiet then, but will satisfy most users. Fans of many other power supplies, starting from 400W models, work at the same or even higher speed under low loads.
When the load grows higher, the fan speed increases linearly, reaching a maximum of 1900rpm. That’s quite a modest top speed for a fan of such a high-wattage PSU. I personally have seen louder PSUs. Of course, the fan is quite noisy at 1400rpm (800W load) and higher speed, but I don’t think it is easy to create such a high load in a real computer while keeping the other components, besides the PSU, quiet.
The temperature difference at the input and output of the PSU is quite normal: less than 14°C at a load of 1300W.
Thus, notwithstanding its huge wattage the Xigmatek NRP-HC1501 is quite a good modern PSU in terms of noisiness. People who love silence should consider specially optimized models instead.
Efficiency and Power Factor
The PSU boasts high efficiency at medium loads – over 85%! The efficiency is lowering towards higher loads, dropping below 80% at 1250W.
+5Vsb Standby Source
Starting from this review I will test the ability of the PSU’s standby source to cope with the specified load. This test is performed when the PSU is turned off, the +5Vsb source being the only working component in it.
The NRP-HC1501 passes this test (the voltage must be within 5% from 5V) but the voltage sags noticeably, to 4.8V almost, under full load. To remind you, the +5Vsb source powers various USB devices when the computer is in sleep mode (for example, to provide the option of turning the system on from the keyboard). It also powers system memory in Suspend-to-RAM mode (S3).
I will not argue here if 1500 watts of power are really necessary for real-life computing because we are going to dedicate a special review to this problem. Let’s assume they are. Will the Xigmatek NRP-HC1501 be able to provide them? According to my tests, yes. Although our testbed could only load it by 1300W due to the testbed’s limitations, there is no reason for me to think that an extra 200W would change anything in the overall picture. The PSU delivers stable voltages with acceptable voltage ripple and does not heat up much. It has large, but not extremely large, dimensions, and is equipped with all the connectors you may want (perhaps one more SATA power cable would be appropriate).
It is also good that, despite its high wattage, the NRP-HC1501 is no noisier than typical modern PSUs. It will satisfy the majority of not-very-demanding users in this respect.