Working together with our APC SmartUPS SC 620, this PSU was stable at loads up to 385 watts when powered by the mains but could only switch to the UPS’s batteries at loads up to 295 watts.
Cross-Load Voltage Stability
When the computer is idle, the +12V voltage may be 3% off the required level, but this deflection lowers to 1-2% at higher loads. This voltage can deflect by more than 3% only in the unrealistic scenario when there's high load on the +3.3V and +5V rails and low load on the +12V rail.
The +5V voltage is always within 3%. And it only gets more than 2% off the required level when there’s a very low load on the +3.3V and +5V rails.
The +3.3V rail keeps its voltage within 3% of the required level in the typical load range, too. In fact, this voltage is within 2% at most load combinations.
Summing it up, the EA-650 Platinum delivers very stable voltages for a PSU without dedicated voltage regulation. Many PSUs that have the latter can't boast such stability.
Output Voltage Ripple
The high-frequency voltage ripple at full load is conspicuous but meets the requirements of the industry standard.
The same goes for the low-frequency ripple.
The EA-650 Platinum is actually very close to the similarly designed FSP Aurum series in this test.
Temperature and Noise
A poor fan regulation algorithm was our main concern about the FSP Aurum series which are very similar in design to this Antec EA-650 Platinum. So, the good news is that the Antec has more adequate fan regulation. However, it is still rather noisy.
It is cooled by a Yate Loon D12BH-12: a 7-blade 120mm fan with a rated speed of 2300 RPM.
The fan keeps on working at its initial speed until a load of 220 watts. Then it accelerates smoothly. The problem is that the initial speed is as high as 1050 RPM, so the fan can be heard even when the computer doesn’t work at high load. At full load the speed of the fan is over 1800 RPM. In fact, the fan gets annoying at loads of 300 watts and higher.
So again, the initial speed is too high. The fan won't be uncomfortable at 1070 RPM during the day, but most users would want something quieter for the night.
Perhaps replacing the fan with a D12BM-12 (1700 RPM) or even D12BL-12 (1200 RPM) would help since such fans are quite capable of coping with the high-efficiency PSU. As it is, the EA-650 Platinum is rather too noisy, even though not as noisy as the FSP Aurum series we tested earlier.
Efficiency and Power Factor
At the reference loads of 20%, 50% and 100% the EA-650 Platinum is 89.1%, 92.7% and 89.8% efficient. Its peak efficiency, as measured in our test, was 92.9% at a load of 334 watts.
That’s an excellent result but we must note that the PSU stopped almost 1% short of the Platinum standard according to our numbers, even though we connect PSUs to 220V mains in which they are a little more efficient than in 115V mains used for the 80 PLUS certification.
This model is officially listed among 80 PLUS Platinum products with results of 90.52%, 92.03% and 89.01%, so this discrepancy must be due to some measurement inaccuracies of our testbed, especially at low loads. We just can’t afford the high-precision testing equipment used by the certification organizations.
By the way, our results match the official ones (considering the different mains) well enough at the medium and maximum loads.
The power factor of this PSU is over 99% at high loads, which is a very good result.
The standby source copes with its job without any problems.
Although extremely efficient and stable in terms of its output voltages, this PSU is not perfect. It even has a serious downside in the end-user’s eyes: it’s too noisy. Its fan regulation algorithm has improved compared to the FSP Aurum series we tested earlier but the speed of the fan seems to be too high at any load. It’s just unreasonable to make the fan work at 1000 RPM at low loads and 1800 RPM at high loads in such a highly efficient PSU that doesn’t get as hot as to require such intensive cooling.