[nextpage title=”Introduction”]
The Aurum Pro is the latest 80 Plus Gold power supply series from FSP, available in 850 W, 1,000 W, and 1,200 W versions. For these higher-wattage models, FSP decided to use a completely new design. Instead of using the cheaper active clamp reset forward design they used on their Aurum Gold and Aurum CM Gold series, they decided to go with a resonant design using two transformers. Let’s see if the 850 W model is worth our recommendation.
Figure 1: FSP Aurum Pro 850 W power supply
Figure 2: FSP Aurum Pro 850 W power supply
The FSP Aurum Pro 850 W is 7.1” (180 mm) deep, using a 135 mm hydro dynamic bearing fan on its bottom (Power Logic PLA13525S12M).
The modular cabling system from this power supply has nine connectors, one for an EPS12V or a video card power cable, two for video card power cables, four for peripheral and SATA power cables, and two for fans. The unit comes with the main motherboard cable, an ATX12V/EPS12V cable, and a video card power cable permanently attached to it. They use nylon sleeves that come from inside the unit. This power supply comes with the following cables:
- Main motherboard cable with a 24-pin connector, 21.6” (55 cm) long, permanently attached to the power supply
- One cable with two ATX12V connectors that together form an EPS12V connector, 26” (66 cm) long, permanently attached to the power supply
- One cable with one EPS12V connector 25.6” (65 cm) long, modular cabling system
- One cable with two six/eight-pin connectors for video cards, 22.4” (57 cm) to the first connector, 4” (10 cm) between connectors, permanently attached to the power supply
- Three cables, each with two six/eight-pin connectors for video cards, 22” (56 cm) long to the first connector, 4” (10 cm) between connectors, modular cabling system
- One cable with four SATA power connectors, 21.6” (55 cm) to the first connector, 5.9” (15 cm) between connectors, modular cabling system
- Two cables, each with two SATA power connectors and two standard peripheral power connectors, 21.6” (55 cm) to the first connector, 5.9” (15 cm) between connectors, modular cabling system
- One cable with two SATA power connectors, two standard peripheral power connectors, and one floppy disk drive power connector, 21.6” (55 cm) to the first connector, 5.9” (15 cm) between connectors, modular cabling system
- Two cables, each with one standard peripheral power connector and one three-pin fan power connector, 22” (56 cm) to the first connector, 6.3” (16 cm) between connectors, modular cabling system
All wires are 18 AWG, which is the minimum recommended gauge, except the ATX12V/EPS12V cable that is permanently attached to the power supply, which uses ticker 16 AWG wires.
The cable configuration is outstanding for an 850 W power supply, allowing you to install up to four video cards that require two auxiliary power connectors each. If the fourth video card power cable is installed, you can’t install the second EPS12V cable, since their connector is shared. Another highlight of this power supply is the presence of two cables for fans, where the speed of the fans is controlled according to the power supply temperature. The presence of 10 SATA power connectors is adequate for a high-end unit.
Figure 3: Cables
Let’s now take an in-depth look inside this power supply.
[nextpage title=”A Look Inside the FSP Aurum Pro 850 W”]
We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our “Anatomy of Switching Power Supplies” tutorial to understand how a power supply works and to compare this power supply to others.
On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.
Figure 4: Top view
Figure 5: Front quarter view
Figure 6: Rear quarter view
Figure 7: The printed circuit board
[nextpage title=”Transient Filtering Stage”]
As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.
In the transient filtering stage, this power supply is flawless. It uses an integrated circuit called “CAPZero” (CAP007DG) to reduce power loss.
Figure 8: Transient filtering stage (part 1)
On the next page, we will have a more detailed discussion about the components used in the FSP Aurum Pro 850 W.
[nextpage title=”Primary Analysis”]
On this page we will take an in-depth look at the primary stage of the FSP Aurum Pro 850 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.
This power supply uses two LL15XB60 rectifying bridges, which are attached to an individual heatsink. Each bridge supports up to 15 A at 124° C. So in theory, you would be able to pull up to 3,450 W from a 115 V power grid. Assuming 80% efficiency, the bridges would allow this unit to deliver up to 2,760 W without burning themselves out (or 3,105 W with 90% efficiency). Of course, we are only talking about these particular components. The real limit will depend on all the components combined in this power supply.
Figure 10: Rectifying bridges
The active PFC circuit uses three STF26NM60N MOSFETs, each one supporting up to 20 A at 25° C or 12.6 A at 100° C in continuous mode (note the difference temperature makes), or 80 A at 25° C in pulse mode. These transistors present a 165 mΩ resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.
Figure 11: Active PFC diode and transistors
The active PFC circuit is managed by an ICE2PCS02 active PFC controller.
Figure 12: Active PFC controller
The output of the active PFC circuit is filtered by two 330 µF x 420 V Japanese electrolytic capacitors, from Matsushita (Panasonic), labeled at 105° C and connected in parallel. This is the equivalent of one 660 µF x 420 V capacitor.
In the switching section, two STW26NM60N MOSFETs are employed using a resonant configuration. These transistors have the exact same specifications as the transistors used in the active PFC circuit. The only difference between them is the packaging (TO-220FP vs. TO-247).
Figure 13: Switching transistors
The switching transistors are controlled by a CM6901 resonant controller.
Figure 14: Resonant controller
This power supply uses two transformers with their primary connected in series instead of using a single transformer. This allows the use of two small transformers instead of a single big one, and also provides better cooling. In Figure 15, you can also see the coil required by the resonant design.
Figure 15: The two transformers
Another interesting feature present in the primary of this power supply that is worthwhile mentioning is the presence of a SENZero chip (SEN012DG), which reduces the amount of energy the power supply consumes when in standby mode.
Figure 16: The SENZero chip
Let’s now take a look at the secondary of this power supply.
[nextpage title=”Secondary Analysis”]
As one would expect in a high-efficiency power supply, the FSP Aurum Pro 850 W uses a synchronous design, where the Schottky rectifiers are replaced with MOSFETs. Also, the reviewed product uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Both designs are used to increase efficiency.
The +12 V output uses four IPD036N04L G MOSFETs, each one supporting up to 90 A at 25° C or 87 A at 100° C in continuous mode, or up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of only 3.6 mΩ. These transistors are located on the solder side of the printed circuit board, and the power supply housing is used as a heatsink for these transistors.
Figure 17: The +12 V transistors
As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters, which are located on a single daughterboard soldered to the main printed circuit board. In Figures 18 and 19, you can see the physical aspect of this card. The converters are controlled by an APW7158 integrated circuit, using four APM3116N and four APM3109N MOSFETs. Unfortunately, datasheets for these components are not available on their manufacturer’s website.
Figure 18: The DC-DC converters
Figure 19: The DC-DC converters
This power supply uses a PS223 monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP), and over current (OCP) protections, with four channels (+12V1, +12V2, +5 V, and +3.3 V). The manufacturer decided to use only one of the +12 V over current protection channels, making this unit a single-rail design.
Figure 20: Monitoring circuit
The electrolytic capacitors that filter the +12 V output are solid, from CapXon. (Some standard Japanese electrolytic capacitors, from Rubycon and Chemi-Con, are also used.)
[nextpage title=”Power Distribution”]
In Figure 21, you can see the power supply label containing all the power specs.
Figure 21: Power supply label
This unit has a single +12 V rail, so there is not much to talk about here.
How much power can this unit really deliver? Let’s find out.
[nextpage title=”Load Tests”]
We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.”
First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.
If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.
The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, the +12VA and +12VB inputs were connected to the power supply’s single +12 V rail. (The +12VB input was connected to the power supply EPS12V connector that is permanently attached to the unit.)
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 6 A (72 W) | 13 A (156 W) | 19 A (228 W) | 25.5 A (306 W) | 32 A (384 W) |
| +12VB | 6 A (72 W) | 13 A (156 W) | 19 A (228 W) | 25.5 A (306 W) | 31.5 A (378 W) |
| +5 V | 1 A (5 W) | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) |
| +3.3 V | 1 A (3.3 W) | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4 W) |
| +5VSB | 1 A (5 W) | 1.5 A (7.5 W) | 2 A (10 W) | 2.5 A (12.5 W) | 3 A (15 W) |
| -12 V | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) |
| Total | 165.6 W | 346.6 W | 508.6 W | 684.8 W | 850.2 W |
| % Max Load | 19.5% | 40.8% | 59.8% | 80.6% | 100.0% |
| Room Temp. | 46.8° C | 45.3° C | 45.4° C | 46.9° C | 49.4° C |
| PSU Temp. | 44.5° C | 45.5° C | 45.8° C | 46.7° C | 50.8° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 185.1 W | 381.3 W | 565.1 W | 770.0 W | 978.0 W |
| Efficiency | 89.5% | 90.9% | 90.0% | 88.9% | 86.9% |
| AC Voltage | 117.3 V | 115.2 V | 113.3 V | 111.0 V | 108.5 V |
| Power Factor | 0.993 | 0.997 | 0.998 | 0.998 | 0.998 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The FSP Aurum Pro 850 W passed our tests, with efficiency between 86.9% and 90.9%, correctly matching the 80 Plus Gold certification, which requires minimum efficiency of 87% at light (i.e., 20%) and full loads, and minimum efficiency of 90% at typical (i.e., 50%) loads.
Voltage regulation was excellent, with all voltages closer to their nominal values (3% regulation) during all tests, except for the -12 V output during test one (at -11.61 V) and +5VSB output at test five (at +4.83 V). These outputs, however, were still inside the allowed range. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.
Let’s discuss the ripple and noise levels on the next page.
[nextpage title=”Ripple and Noise Tests”]
Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.
The FSP Aurum Pro 850 W provided low ripple and noise levels, as you can see in the table below.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 39.4 mV | 40.4 mV | 39.2 mV | 45.8 mV | 51.4 mV |
| +12VB | 37.0 mV | 38.2 mV | 37.6 mV | 47.4 mV | 53.4 mV |
| +5 V | 14.2 mV | 19.2 mV | 23.2 mV | 27.6 mV | 32.8 mV |
| +3.3 V | 12.6 mV | 15.0 mV | 19.2 mV | 23.2 mV | 27.2 mV |
| +5VSB | 12.2 mV | 14.0 mV | 16.4 mV | 18.4 mV | 24.0 mV |
| -12 V | 38.4 mV | 40.4 mV | 38.8 mV | 43.8 mV | 47.4 mV |
Below you can see the waveforms of the outputs during test five.
Figure 22: +12VA input from load tester during test five at 850.2 W (51.4 mV)
Figure 23: +12VB
input from load tester during test five at 850.2 W (53.4 mV)
Figure 24: +5V rail during test five at 850.2 W (32.8 mV)
Figure 25: +3.3 V rail during test five at 850.2 W (27.2 mV)
Let’s see if we can pull more than 850 W from this unit.
[nextpage title=”Overload Tests”]
Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. We couldn’t evaluate the protections of this power supply, as we were limited by our load tester, which can only pull up to 1,000 W. Furthermore, we couldn’t pull more from this power supply to see if it would burn or shut down. During this extreme configuration, noise and ripple levels were still below the maximum allowed, and voltages were still inside the proper range.
| Input | Overload Test |
| +12VA | 33 A (396 W) |
| +12VB | 33 A (396 W) |
| +5 V | 23 A (115 W) |
| +3.3 V | 23 A (75.9 W) |
| +5VSB | 3 A (15 W) |
| -12 V | 0.5 A (6 W) |
| Total | 998.6 W |
| % Max Load | 117.5% |
| Room Temp. | 44.6° C |
| PSU Temp. | 49.5° C |
| AC Power | 1,199.0 W |
| Efficiency | 83.3% |
| AC Voltage | 106.3 V |
| Power Factor | 0.999 |
[nextpage title=”Main Specifications”]
The main specifications for the FSP Aurum Pro 850 W power supply include:
- Standards: ATX12V 2.3 and EPS12V 2.92
- Nominal labeled power: 850 W
- Measured maximum power: 998.6 W at 44.6° C
- Labeled efficiency: 80 Plus Gold, 87% minimum at light (i.e., 20%) and full loads, 90% minimum at typical (i.e., 50%) load
- Measured efficiency: Between 86.9% and 90.9%, at 115 V (nominal, see complete results for actual voltage)
- Active PFC: Yes
- Modular Cabling System: Yes
- Motherboard Power Connectors: One 24-pin connector and two ATX12V connectors that together form an EPS12V connector, permanently attached to the power supply, and one EPS12V connector on the modular cabling system
- Video Card Power Connectors: Two six/eight-pin connectors on one cable permanently attached to the power supply and six six/eight-pin connectors on three cables on the modular cabling system
- SATA Power Connectors: 10 on four cables, modular cabling system
- Peripheral Power Connectors: Six on three cables, modular cabling system
- Floppy Disk Drive Power Connectors: One
- Protections (as listed by the manufacturer): Over voltage (OVP), under voltage (UVP), over current (OCP), over power (OPP), over temperature (OTP), and short-circuit (SCP) protections
- Are the above protections really available? Couldn’t test
- Warranty: Five years
- More Information: https://www.fspgroupusa.com
- Average Price in the U.S.*: USD 180.00
* Researched at Newegg.com on the day we published this review.
[nextpage title=”Conclusions”]
The FSP Aurum Pro 850 W is a step above other 80 Plus Gold power supplies from FSP thanks to its improved design. For the higher-wattage models, FSP decided to go with a resonant design using two transformers, which is superior to the cheaper active clamp reset forward design. The obvious side effect is a higher price tag. However, at USD 180, it is still a very competitive power supply for the high-end enthusiast. For instance, the Enermax Platimax 850 W costs USD 250 and brings efficiency only two points higher, and other 850 W units with the 80 Plus Gold certification are in the same price range (USD 180 – USD 200).
The main competitor for the FSP Aurum Pro 850 W is the Corsair AX850W, which is also a great power supply, but this model from FSP achieved higher efficiency during our tests, and brings the fan control cables, which don’t exist on competing products. Another great advantage of the reviewed unit is the out-of-the-box support for four high-end video cards.
Of course, if you are an average user, there are more affordable, good-quality power supplies with high efficiency out there. However, if you are an enthusiast building a computer with several video cards and want “the best” power supply around, the new FSP Aurum Pro 850 W is the product for you.
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