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Nexus NX-4090 400watt PSU |
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Written by Mikhail Ivanenkov
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Monday, 18 June 2007 |
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Page 3 of 3
Power consumption here is nowhere near 400watts. Although I have a somewhat outdated system it is by no means archaic and I can still play any games out there, though not as well as I'd like to. The point is, you don't need a 500watt PSU even for the "ultimate" computer (assuming it's not powering anything extreme like peltiers). That said, the loader demands 138watts from a host PSU. The NX-4090 drew in 182watts of AC power. The difference (44watts) was given off as heat. This makes our candidate ~75.8% efficient, which is decent considering the industry standard is 68% an in tune with other Fortron-based PSUs, though not as high as certain Seasonic or Enermax PSUs.
The VA (volts x amperes) measurement is very helpful in determining the PFC (Power Factor Correction) value of a power supply. This is a percentage measurement (similar to efficiency) which shows how much power is lost in harmonics. PSUs without any PFC run at about 0.5-0.7, meaning as much as half the electricity coming from a source (i.e. wall socket) is being completely wasted. While it doesn't affect the performance of the PSU, this has a major impact on your energy bill especially if you have a power hungry machine that runs 24/7.
PSUs with passive PFC range from 0.6-0.8; those with active range from 0.95-0.99 meaning almost all of the energy is being utilized by the power supply. PFC is calculated as follows: PF = wattage / VA. PFC at extremely low output levels isn't very important and neither is it representative of the actual PFC so the 0.48 reading (at only 6watts of energy usage) is irrelevant. More important is the 0.63-0.64 value: only 63-64% of energy is being used. While this is standard for a PSU with passive PFC, I was disappointed to find a lack of active PFC in the NX-4090.
Idle:
Load:
Finally I decided to check voltage stability. For this I ran MBM for hour long intervals recording values every 5 seconds and taking the average. Idle testing showed an average of 3.32V on the 3.3V line (0.6% difference), 4.89V on the 5V line (2.2% difference) and 12V on the 12V line (no difference). These are rock solid values and well within acceptable tolerances. Load readings painted a similar picture: 3.31V on the 3.3V line (0.3% difference), 4.83V on the 5V line (3.4% difference) and 12.01V on the 12V line (0.1% difference).
All in all the NX-4090 is a solid PSU. It boasts good specs, has very stable lines and manages to stay cool while generating a trivial amount of noise. It also looks nice and would have been a prime choice on my list if not for the use of passive PFC especially since it doesn't come cheap ($110 ought to burn a nice hole in your wallet). Although active PFC is relatively new, manufacturers are quickly catching on and I encourage Nexus to do the same.
Pros
- Nicely packaged/good presentation
- Good looking and well constructed
- SATA connectors
- Silent beyond a few inches
- Solid performance and cool operation
Cons
- Needs cable sleeving
- Passive PFC
- Expensive ($110)
Nexus has made a strong entrance into the quiet PC enthusiast market. The NX-4090 is a well built power supply and a good performer. The problem is the lack of active PFC and consequently the price. $110 is a lot to ask for a PSU that drains close to 40% the electricity it requires (before efficiency is even calculated). Nevertheless, silence doesn't come cheap and if you can deal with the higher energy bill, go for it. You can snag one here and start saying goodbye to noise one fan at a time.
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Last Updated ( Monday, 18 June 2007 )
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