The PSU worked normally at full load notwithstanding the modest size of its heatsinks.
Alas, the very first test shows that the PSU is not quite all right. The output voltage ripple at full load is slightly above the norm on every power rail. The pulsation is high on the +12V rail due to short-term spikes meaning that the manufacturer should have used better electrolytic capacitors that would filter the high-frequency noise more effectively.
By the way, the FSP Group website shows 140 millivolts for the 12V rail and 75 millivolts for the other rails as the allowable maximums in the PSU’s specs but I want to remind you that ATX12V Power Supply Design Guide suggests other maximums: 120 millivolts for the +12V rail and 50 millivolts for the other rails. So, the FSP Epsilon 1010 does not even formally comply with the industry standard.
The cross-load characteristics are no better: the +12V voltage is too high at minimum loads while the +5V voltage sags at high loads. The Epsilon 1010 doesn’t look good even in comparison with many PSUs with joint voltage regulation, let alone models with dedicated voltage regulation which are a majority of 1000W PSUs.
The PSU is cooled with a Protechnic Electric fan (120x120x25mm, MGA12012YB-O25). It is not highlighted despite the translucent impeller. The On/Off switch is the only shining detail in the whole PSU.
The fan speed is adjusted linearly depending on load, reaching 1500rpm at 350W. The fan accelerates to 2900rpm at full load, which is a very high – and noisy – speed for a 120mm impeller.
So, the Epsilon 1010 is noisier than average although it doesn’t heat up much: the temperature difference is no bigger than 10°C.
The efficiency is traditionally superb. Although it lowers towards full load, its maximum is as high as 87%. The Epsilon series and other models based on the same platform have proved their high efficiency many times already.
The previous three PSUs could be said to have minor drawbacks, but the FSP Epsilon 1010 can only be viewed as having very few advantages such as its small size. However, these do not make up for its shortcomings: noisy operation, poor voltage stability, and too-high output voltage ripple.