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Review: Antec EarthWatts Platinum 650W

by Tarinder Sandhu on 30 December 2011, 09:00 4.0

Tags: Antec

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The numbers

Our testing procedures can be found at this link.


Load 10pc 25pc 50pc 75pc 100pc
Efficiency 83.3pc 90.0pc 93.4pc 91.0 90.2pc

The 10pc load equates to 62W of load - it's not an exact figure as the various lines have to be loaded with particular amps/volts that may not exactly map out to the desired number.

Those who think that such a figure is pointless for a 650W PSU may like to know that an Intel Core-i5 2500K system with 8GB of RAM and a super-high-end Radeon HD 7970 graphics card idles at just 42W, and that's measured at the wall. Knowing efficiency at low-load levels is just as important as at, say, 50 per cent or 75 per cent.

The efficiency figures just about meet the criteria for Platinum, as set out by 80 PLUS, but it's a close call, going by our measurements.


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 -0.9pc +1.0pc +1.2pc
50 per cent -1.4pc 0.3pc +1.0pc
100 per cent -2.2pc -2.8pc +0.9pc

The supply performs within specification but isn't as good at regulating voltage as, say, the XFX ProSeries 1,250W, though do know that it's half the price.

Regulation - cross-load

How about providing uneven loads that stress particular voltage rails? In the first attempt, we've put 48A 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 15A 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 -2.5pc -2.2 -3.1pc
Cross-load 3.3V/5V focus -1.7pc -2.6pc +3.1pc

Numbers fall within specification and there's little to be worried about. We'd like them closer to the ideal, but even pushing and pulling the supply's power-delivery system can't throw it off.


Line/Load (mv - p-p max) 3.3V 5V 12V
10 per cent 15mV 20mV 20mV
50 per cent 15mV 20mV 25mV
100 per cent 20mV 30mV 55mV

The ATX v2.2 spec states that the maximum permissible ripple is 120mV for the 12V line and 50mV for others.

Ripple is just above average with respect to the PSUs we've previously tested. In ripple-speak it's a fairly quiet PSU until stressed with 100 per cent load, where it can get noisy. But our commentary compares it against a perfect supply and there is no such thing. Again, and repeating ad nauseam, it's well within ATX specifications.


Temperatures Intake Exhaust
10 per cent 29°C 33°C
50 per cent 32°C 35°C
100 per cent 35°C 45°C

Good temps all round. You'd expect it to become warmer when loaded to 100pc for extended periods. We reckon the low-ish temperatures are a function of the relatively low power it has to push out: imagine trying to keep a 1,500W PSU cool!

We'd normally report the noise rating, but such is the din produced by the Chroma machine - ears are still ringing - that doing so would be completely pointless.

However, subjective analysis finds that the supply is very quiet at low loads - those under 300W - and the fan only becomes noticeable, though not aurally offensive, at 400W-plus.

Results recap

Very good on efficiency and reasonable in other areas.