FSP Aurum Xilenser AU-500FL 500W

FSP is one of the largest manufacturers for OEM power supplies and adapters. Now they're launching a new fanless series, the "Aurum Xilenser", for users that want absolute silence. We have the AU-500FL on our test bench today. Like the previous Aurum offerings, the new generation is 80 Plus Gold certified.

The casing for the AU-500FL has more ventilation holes than we're used to seeing, with perforations on practically every available spot! Besides the bottom (where a large fan might normally sit) and the back, Fortron has holes on the front and sides of the casing. Even the top (not shown, and assuming a top-mounted PSU; otherwise this is the "bottom") has a few extra holes to help with cooling. With no fan, there's obviously a need to remove heat and the extra ventilation should help in that regard. Of course, even a very slow fan would help a lot more, and perhaps a good CPU heatsink with a large, low-RPM 120mm fan is just what the doctor ordered. If you still want to be completely fanless, though, we'd exercise extreme caution before trying to stuff in 500W of components and other hardware!

Package Contents and Power Rating

FSP offers a few extras in the package. Besides the common 10A power cable and four screws, you get a sticker with an FSP logo, a short user manual, some cable ties, and all the modular cables. Features include the flat modular cables, 80 Plus Gold certification ("ultra high efficiency"), and those arrow-shaped ventilation holes. In addition FSP implemented all important safety functions. Of course the PSU is ErP-Ready.

Rated at up to 492W, the two +12V rails can deliver nearly the full output power of this PSU. +3.3V and +5V are rated at a maximum capacity of 20A each, with a combined output of just 100W. Like most modern high-efficiency power supplies, FSP has DC-to-DC converters inside to improve voltage regulation. This is one reason for the high power rating on +12V.

External Impressions, Cables and Connectors

As mentioned before FSP uses arrow-shaped ventilation holes on all sides. The AU-500FL has a connection panel for modular cables and a description for every plug-type. The rugged and very thick material is strongly reminiscent of some Enermax power supplies. It's too bad that these two golden-colored parts on the top are made out of cheap plastic.

Except the main cables with 24 pins all harnesses are removable. The 4+4 pin ATX12V, the 6/8-pin, as well as the peripheral cables are longer than 60cm, which is awesome for anyone with a larger computer case. The first peripheral cable offers three SATA connectors from 55cm to 85cm in 15cm steps. Another harness provides two HDD and one SATA connectors from 55cm to 85cm. The 24-pin motherboard connector is 55cm, which is also nice. The PCIe plug sockets have the same color like the ones for the peripheral components.

Internal Design and Components

FSP uses a new design and no active clamp this time, but basically this PSU consists of some well known technologies. Two large main caps are more than enough for a 500W PSU and FSP has chosen two nice Panasonic devices; there are some Japanese caps on the secondary side as well. You can see the heatsinks for the VRMs (top right) and even larger ones for the Power Factor pre-regulator. The inlet filtering is extensive but there is no MOV. A PS223 offers the safety functions on the secondary side, including OCP. The voltage pulses of the resonant circuit run nearly sinusoidal and the transistors turn on at zero voltage. Together with the low resistance on the drain-source path the power dissipation is much lower during turn-on, turn-off, and the saturation of those transistors. The overall design definelty looks like a Seasonic X-460FL with different caps and no full line filtering stage on the AC plug.

Voltage Regulation

Noise Levels

Efficiency and PFC

Since there is no fan, there's not much point in measuring sound pressure levels, but what about noise from the electronics? There is an audible "chirping" from the PFC choke and both DC-to-DC converters. However, this could be an individual case. The difference between the ambient and the exhaust temperature is relatively high. We've tested the power supply with a room temperature of just 22.1 °C, which is usually no problem for a high-quality PSU.

The voltage quality is absolutely acceptable. Small transients are no big deal and the smaller rails are always below 25mV which is less than 0.5% ripple. +12V shows only 51mV,  but we should keep in mind that Seasonic had no more than 20mV on all outputs. Overall the voltage regulation is decent. There is hardly any drop on the +12 V and +3.3V rail but +5 V could be closer the optimal value.

Considering the 80 Plus Gold certification, we expected high efficiency and that's exactly what we got. The only blemish is that 5% load "only" comes in at 71-74%. At this point the efficiency could be better than 75%, but we don't want to overdo things.

Conclusion

We'd like to make a comparison as always, but we have to wait for more information on pricing and availability first. However, the FSP Aurum Xilenser AU-500-FL offers a good performance and a modular connector panel as well. The worst thing we can say about the performance is that it has higher ripple results than Seasonic (X-460FL) and the electronics could be more silent.

The AU-500FL reached up to 92% efficiency (230V), with no more than 25mV ripple and noise on the smaller outputs and tolerable voltage regulation. There's no fan for cooling, but the electronics made an audible noise this time. Even so the PSU is close to what we'd expect: almost silent. But we should keep in mind that there's some serious competition from Seasonic's product line.

The AU-500FL has four PCIe connectors—quite nice for a passively cooled PSU. All of the cables are longer than 55cm as well, so you can safely use this unit in some larger cases. All the chosen components are upscale and the design and topology is flawless. There is a well equipped filtering behind the entrance and Japanese capacitors are used throughout the PSU (except some all solid caps). The transistors are well dimensioned and FSP offers all the expected safety functions. It should be noted that this PSU looks exactly like a X-460FL without a line filtering stage but multiple +12V outputs.

We definitely look forward to seeing FSP's fanless series in all markets, as passively cooled PSUs are rare. FSP is able to provide a good product that is nearly as good as the solution from Seasonic. In summary, it can be stated that the AU-500FL is recommendable for most PSU enthusiasts if they charge a good price.