The benchmark gauntlet
Our testing procedures can be found at this link.
Efficiency
| Load | 10pc | 25pc | 50pc | 75pc | 100pc |
|---|---|---|---|---|---|
| Efficiency | 85.6pc | 91pc | 91.4pc | 88.3pc | 87.2pc |
Efficiency is about as good as it gets for an 80 PLUS Gold-rated supply. The numbers are very, very close to those obtained on a Corsair Platinum-certified PSU.
Regulation
In terms of regulation, we're looking at just how well the supply is able to hold to the various lines. The ATX spec. has a +/- 5 per cent leeway on all but the -12V line.
| Line/Load | 3.3V | 5V | 12V |
|---|---|---|---|
| 10 per cent | +0.5pc | +1.6pc | +1.9pc |
| 50 per cent | 0pc | +1pc | +1.3pc |
| 100 per cent | -1.5pc | -0.2pc | +0.5pc |
Most supplies overvolt with little load and undervolt when stressed. The numbers are pretty good, with a maximum 2.4 per cent deviation from best to worst, but they're not quite as stellar as a few recent Seasonic-made supplies that keep this high-to-low regulation below two per cent. Bear in mind that the Enermax figures are well inside those demanded by the ATX specification.
Regulation - cross-load
How about providing uneven loads that stress particular voltage rails? In the first attempt, we've put 65A on the 12V rails, and 1A on the 3.3V and 5V rails. This can actually be somewhat typical for a system heavy on graphics and CPU power. In the second, we've turned the tables and gone for 12A on both the 3.3V and 5V rails - highly unlikely in a real-world environment - and just 2A on the 12V - even more unlikely!
| Line/Load | 3.3V | 5V | 12V |
|---|---|---|---|
| Cross-load 12V focus | -0.7pc | +1.0pc | +1.0pc |
| Cross-load 3.3V/5V focus | -1.7pc | +1.3pc | +2.2pc |
Hammering one part of the PSU power delivery while using just a small portion of the other can throw cheaper supplies of out kilter. The variation is bigger when cross-loading, up to 3.2 per cent on the 12V line, but it remains solid for the class of supply.
Ripple
| Line/Load (mv - p-p max) | 3.3V | 5V | 12V |
|---|---|---|---|
| 10 per cent | 10mV | 15mV | 15mV |
| 50 per cent | 20mV | 15mV | 25mV |
| 100 per cent | 25mV | 25mV | 30mV |
The ATX v2.2 spec states that the maximum permissible ripple is 120mV for the 12V line and 50mV for others.
PSUs convert AC power into DC, but doing so requires the AC waveform to be suppressed. What we're really testing here is the quality of the supply's rectifier and any smoothing capacitors in getting rid of this unwanted up-and-down ripple.
Per-line ripple is good if not outstanding. Here's the skinny: any power supply from a reputable manufacturer is more than likely to comfortably exceed the rather conservative ATX specification. There are ever-so-small differences between what we'd call above-average and truly excellent supplies. Enermax's Revolution87+ fits between these two categories, we feel.
Temps
| Temperatures | Intake | Exhaust |
|---|---|---|
| 10 per cent | 29°C | 32°C |
| 50 per cent | 35°C | 38°C |
| 100 per cent | 39°C | 43°C |
The fan is practically inaudible until the Chroma load is increased to close to 100 per cent. The unit remains pretty cool, too.
Fan performance
Temps are good but they mean little in isolation. Obtaining accurate noise readings is near-on impossible when the supply is connected to the Chroma test harness and dual-unit load-tester. We can test the manufacturer's quietness claims in a different way, by using an AMPROBE TMA10A anemometer placed directly over the centre of the PSU. The anemometer records the airflow being pushed/pulled from the PSU's fan. We can use a Voltcraft DT-10L RPM meter to measure the rotational speed of the fan, too.
| Load | Fan RPM | Airflow | Noise |
|---|---|---|---|
| 10 per cent | 400rpm | circa-15cfm | Silent |
| 50 per cent | 650rpm | circa-25cfm | Very quiet |
| 100 per cent | 1,150rpm | circa-60-70cfm | Quiet |
Put it in our high-end PC and we absolutely cannot hear the Twister fan over the quiet noise generated by an Intel Core i7-3770K and AMD Radeon HD 7990 dual-GPU graphics card.
