Temperature and Noise
The Hiper K800 is cooled by the same fan as we’ve seen in the Hiper M600 above, except for colors. The fan itself is now silvery and its highlighting is blue rather than red.
The K800 has no overheat problems. The outgoing air is almost as cold as the incoming one even at maximum load but what's the tradeoff?
The fan accelerates quickly as soon as you turn the computer on. Starting up from 1000 RPM at a load of 50 watts, the fan hits its top speed of 1800 RPM at 300 watts and keeps it until the full load of 800 watts.
With this fan regulation, the PSU is merciless to its user in terms of acoustic comfort.
Connected to my APC SmartUPS SC 620, this PSU was stable at loads up to 365 watts when powered by the mains but couldn’t switch to the UPS batteries even when the load was as low as 280 watts.
Output Voltage Stability
A PSU with dedicated voltage regulation can be expected to deliver stable voltages at any load.
Indeed, the voltage on the +12V rail always remains within 3% of the default level and even fits within 1% at loads of 250 watts and higher.
There are no problems with the +5V rail, either. This voltage is going to deflect no more than by 2% in the typical load range.
The +3.3V rail is somewhat worse. This voltage deflects by 4-5% when there is a low load on it as well as on the +12V rail, which is typical of a modern computer in idle mode. This shouldn’t be a problem for a top-end configuration that needs a considerable amount of power even when idle, but an energy-efficient computer’s HDDs may get finicky about such deflections in idle mode, even though the voltage does remain within the standard-defined limits.
Output Voltage Ripple
The output voltage ripple on the +12V and +5V rails is conspicuous, yet much lower than the permissible limits.
The voltage ripple is also low at the double frequency of the mains.
Efficiency and Power Factor
The power factor is just what you can expect from a PSU with active PFC whereas the efficiency is inferior to that of Hiper's junior model.
Although Andyson Performance E series PSUs are 80+Bronze certified, the Hiper K800 wouldn't be able to claim that certification. At 20% load, its efficiency is 0.1% lower than the requirements for 220V mains (80.9% efficiency). At 50% load, its efficiency falls 0.5% short of the 80+ requirements (84.5%). The PSU is 83-84% efficient in the typical load range, but can never hit 85%.
On the other hand, Hiper doesn't certify this PSU for 80+ and its efficiency is indeed “higher than 80%” as promised by the maker. So, there is no misleading the customer here.
+5V Standby Source
The standby source is okay.
Alas, the Hiper K800 falls short of my expectations, despite its advanced circuit design. Its efficiency is rather low and its +3.3V voltage fluctuates too much (even though within the standard-defined limits). That's not what one wants from a modern PSU that claims to be a high-quality product. Like the M600, the Hiper K800 has a rather low max load on the +12V rail, too.
Well, these downsides could be put up with if it were not for its noisiness. The fan regulation algorithm is downright inadequate. The fan begins to accelerate linearly right after you turn your computer on and reaches its maximum speed at a load of only 300 watts.
Hopefully, this only refers to this model because I haven’t heard any noise-related complaints regarding the Hiper K1000.