Asus TUF Gaming 550W Bronze Power Supply Review

The ASUS TUF Gaming 550W Bronze is a budget-oriented PSU that manages to achieve high-performance thanks to the modern platform that it uses. Nevertheless, the competition is rough. Although units like the XPG Pylon 550, Corsair CX650M, and Thermaltake Smart BM2 550 use less-advanced platforms, they still take the lead in overall performance, leaving no room for the TUF Gaming 550 to earn a place in our best PSUs article

The TUF-Gaming series consists of four PSU models with capacities ranging from 450W to 750W. The model we are evaluating here has 550W max power, ideal for a a small home PC with a mid-end GPU or a business-oriented PC with an embedded GPU. To keep the production cost low, ASUS used a non-modular but modern design provided by Great Wall. This is the same platform found in the Corsair CX line, which has been replaced by the CX-M line that might utilize a semi-modular design but also uses a less advanced platform than CX. 

The TUF 550 is 80 PLUS Bronze, and Cybenetics Silver certified in efficiency. In noise, it received a Cybenetics Standard++ rating, which is not so flattering for a low-capacity PSU, especially one using a modern platform. Its dimensions are standard, with 150mm depth, allowing the installation of a 135mm fan. 

Specifications of Asus TUF Gaming 550W

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Manufacturer (OEM) Great Wall
Max. DC Output 550W
Efficiency 80 PLUS Bronze, Cybenetics Silver (85-87%)
Noise Cybenetics Standard++ (30-35 dB[A])
Modular ✗ (fixed)
Intel C6/C7 Power State Support
Operating Temperature (Continuous Full Load) 0 – 40°C
Over Voltage Protection
Under Voltage Protection
Over Power Protection
Over Current (+12V) Protection
Over Temperature Protection
Short Circuit Protection
Surge Protection
Inrush Current Protection
Fan Failure Protection
No Load Operation
Cooling 135mm Double Ball-Bearing Fan (CF1325H12D)
Semi-Passive Operation
Dimensions (W x H x D) 150 x 85 x 150mm
Weight 1.92 kg (4.23 lb)
Form Factor ATX12V v2.53, EPS 2.92
Alternative Low Power Mode (ALPM) compatible
Warranty 6 Years

Power Specifications: Asus TUF Gaming 550W Bronze

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Rail Row 0 – Cell 1 3.3V 5V 12V 5VSB -12V
Max. Power Amps 25 20 45.8 3 0.8
Row 2 – Cell 0 Watts Row 2 – Cell 2 120 549.6 15 9.6
Total Max. Power (W) Row 3 – Cell 1 Row 3 – Cell 2 550 Row 3 – Cell 4 Row 3 – Cell 5 Row 3 – Cell 6

Cables & Connectors for Asus TUF Gaming 550W

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Captive Cables Row 0 – Cell 1 Row 0 – Cell 2 Row 0 – Cell 3 Row 0 – Cell 4
Description Cable Count Connector Count (Total) Gauge In Cable Capacitors
ATX connector 20+4 pin (610mm) 1 1 18-20AWG No
4+4 pin EPS12V (820mm) 1 1 18AWG No
6+2 pin PCIe (610mm+100mm) 1 2 18AWG No
SATA (400mm+110mm+110mm) 1 3 18AWG No
SATA (410mm+110mm) 1 2 18AWG No
4-pin Molex (400mm+150mm+150mm+150mm) 1 4 18AWG No
Modular Cables Row 8 – Cell 1 Row 8 – Cell 2 Row 8 – Cell 3 Row 8 – Cell 4
AC Power Cord (1390mm) – C13 coupler 1 1 18AWG

Given its capacity, the PSU has enough cables and connectors. On top of that, the cables are long, especially the EPS, which reaches 810mm! Lastly, the distance between the 4-pin Molex connectors is adequate at 150mm. 

Component Analysis of Asus TUF Gaming 550W

We strongly encourage you to have a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we’re about to discuss.

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General Data
Manufacturer (OEM) Great Wall
PCB Type Single Sided
Primary Side
Transient Filter 4x Y caps, 2x X caps, 2x CM chokes, 1x MOV
Inrush Protection NTC Thermistor 15S1R5M (1.5 Ohm)
Bridge Rectifier(s) 1x GBU15K (800V, 15A @ 100°C)
APFC MOSFETs 2x ROHM R6020ENX (600V, 20A, Rds(on): 0.196Ohm)
APFC Boost Diode 1x NXP BYC8B-600 (600V, 8A)
Bulk Cap(s) 1x Lelon (450V, 330uF, 2,000h @ 105°C, LSG)
Main Switchers 2x STMicroelectronics STF24N60DM2 (600V, 11A @ 100°C, Rds(on): 0.2Ohm)
APFC Controller Champion CM6500UNX & CM03AX
Resonant Controller Champion CM6901X
Topology Primary side: APFC, Half-Bridge & LLC converter
Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12V MOSFETs 4x Advanced Power AP9990GP (60V, 80A @ 100°C, Rds(on): 6mOhm)
5V & 3.3V DC-DC Converters
Filtering Capacitors

Electrolytic: 7x Lelon (4-7,000h @ 105°C, RXW), 2x Teapo (3-6,000h @ 105°C, SY)
Polymer: 1x Elite, 5x Lelon, 2x no info

Supervisor IC IN1S429I – DCG
Fan Model Champion CF1325H12D (135mm, 12V, 0.6A, Double Ball Bearing)
5VSB Circuit
Rectifier 1x PFC PFR30L45CT SBR (45V, 30A)
Standby PWM Controller Power Intergrations TNY278PN

The platform is modern. Typically lower efficiency units use older platforms, with the only modern touch being the DC-DC converters on the secondary side. In this case, though, GW used a half-bridge topology and an LLC resonant converter, a design that we meet in higher efficiency platforms. Moreover, a synchronous design regulates the 12V rail on the secondary side.

The significant compromises that had to be made to keep the cost low were the low-quality bulk and filtering caps and the fixed cables. We don’t mind much about the latter, but we do mind the Lelon caps.

The transient/EMI filter has all require parts and it does an almost perfect job. 

ASUS TUF Gaming 550

(Image credit: Tom’s Hardware)

The single bridge rectifier can handle up to 15A at 100°C.

The APFC converter uses two FETs and a single boost diode. The bulk cap is rated at 450V and 105°C, but its capacity is low, and to make things even worse, it is by Lelon, which is not among the good capacitors brands. 

The primary switching FETs are two STMicroelectronics installed in a half-bridge topology. An LLC resonant converter is also used for increased efficiency. 

Four FETs regulate the 12V rail and a pair of DC-DC converters handle the minor rails. 

The filtering caps are mostly by Lelon and Teapo. The Lelon caps have good specs. Nonetheless, we would prefer if all caps were by Teapo. 

The standby PWM controller is a TNY278PN IC. The rectifier on the secondary side of this circuit is an SBR. 

ASUS TUF Gaming 550

(Image credit: Tom’s Hardware)

The main supervisor IC is an IN1S429I – DCG. 

Soldering quality is good.

The cooling fan uses a double ball-bearing. We didn’t expect to find a quality DBB fan in this PSU. 

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To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units. 

Primary Rails And 5VSB Load Regulation

The following charts show the main rails’ voltage values recorded between a range of 40W up to the PSU’s maximum specified load, along with the deviation (in percent). Tight regulation is an important consideration every time we review a power supply because it facilitates constant voltage levels despite varying loads. 

Tight load regulation also, among other factors, improves the system’s stability, especially under overclocked conditions and, at the same time, it applies less stress to the DC-DC converters that many system components utilize.

Load regulation is decent at 12V and tight on the other rails. The fixed cables help in load regulation because they don’t have the increased resistance of the modular ones. 

Hold-Up Time

Put simply; hold-up time is the amount of time that the system can continue to run without shutting down or rebooting during a power interruption.

The hold-up time is too short. Asus had to use a low-capacity bulk cap to keep the cost low. 

Inrush Current

Inrush current, or switch-on surge, refers to the maximum, instantaneous input current drawn by an electrical device when it is first turned on. A large enough inrush current can cause circuit breakers and fuses to trip. It can also damage switches, relays, and bridge rectifiers. As a result, the lower the inrush current of a PSU, right as it is turned on, the better.

Inrush currents are high. 

Leakage Current

In layman’s terms, leakage current is the unwanted transfer of energy from one circuit to another. In power supplies, it is the current flowing from the primary side to the ground or the chassis, which in the majority of cases is connected to the ground. For measuring leakage current, we use a GW Instek GPT-9904 electrical safety tester instrument.

The leakage current test is conducted at 110% of the DUT’s rated voltage input (so for a 230-240V device, we should conduct the test with 253-264V input). The maximum acceptable limit of a leakage current is 3.5 mA and it is defined by the IEC-60950-1 regulation, ensuring that the current is low and will not harm any person coming in contact with the power supply’s chassis.

ASUS TUF Gaming 550

(Image credit: Tom’s Hardware)

Leakage current is far below the 3.5 mA limit. 

10-110% Load Tests

These tests reveal the PSU’s load regulation and efficiency levels under high ambient temperatures. They also show how the fan speed profile behaves under increased operating temperatures.

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Test 12V 5V 3.3V 5VSB DC/AC (Watts) Efficiency Fan Speed (RPM) PSU Noise (dB[A]) Temps (In/Out) PF/AC Volts
10% 2.758A 1.952A 1.981A 0.982A 54.985 84.165% 0 <6.0 39.44°C 0.953
Row 2 – Cell 0 12.105V 5.122V 3.332V 5.093V 65.329 Row 2 – Cell 6 Row 2 – Cell 7 Row 2 – Cell 8 35.43°C 114.84V
20% 6.535A 2.929A 2.973A 1.179A 109.91 87.93% 0 <6.0 39.99°C 0.978
Row 4 – Cell 0 12.091V 5.12V 3.33V 5.088V 124.996 Row 4 – Cell 6 Row 4 – Cell 7 Row 4 – Cell 8 35.74°C 114.83V
30% 10.667A 3.418A 3.47A 1.377A 164.896 89.031% 0 <6.0 40.62°C 0.986
Row 6 – Cell 0 12.080V 5.119V 3.328V 5.082V 185.209 Row 6 – Cell 6 Row 6 – Cell 7 Row 6 – Cell 8 35.87°C 114.81V
40% 14.827A 3.912A 3.969A 1.576A 219.968 88.161% 1277 30.4 36.37°C 0.989
Row 8 – Cell 0 12.057V 5.112V 3.325V 5.077V 249.507 Row 8 – Cell 6 Row 8 – Cell 7 Row 8 – Cell 8 41.42°C 114.8V
50% 18.650A 4.895A 4.966A 1.774A 274.953 88.029% 1227 29.3 37°C 0.991
Row 10 – Cell 0 12.036V 5.108V 3.322V 5.072V 312.343 Row 10 – Cell 6 Row 10 – Cell 7 Row 10 – Cell 8 42.42°C 114.79V
60% 22.475A 5.877A 5.964A 1.974A 329.938 87.619% 1329 31.6 37.69°C 0.992
Row 12 – Cell 0 12.019V 5.105V 3.32V 5.067V 376.563 Row 12 – Cell 6 Row 12 – Cell 7 Row 12 – Cell 8 43.7°C 114.77V
70% 26.311A 6.86A 6.963A 2.173A 384.934 86.863% 1428 33.7 38.09°C 0.993
Row 14 – Cell 0 12.004V 5.103V 3.318V 5.06V 443.146 Row 14 – Cell 6 Row 14 – Cell 7 Row 14 – Cell 8 45.14°C 114.76V
80% 30.137A 7.844A 7.959A 2.274A 439.349 86.025% 1597 36.7 38.12°C 0.994
Row 16 – Cell 0 11.994V 5.101V 3.315V 5.055V 510.72 Row 16 – Cell 6 Row 16 – Cell 7 Row 16 – Cell 8 46.16°C 114.73V
90% 34.383A 8.333A 8.445A 2.375A 494.311 85.2% 1680 38.3 38.36°C 0.994
Row 18 – Cell 0 11.978V 5.099V 3.314V 5.051V 580.18 Row 18 – Cell 6 Row 18 – Cell 7 Row 18 – Cell 8 47.44°C 114.72V
100% 38.427A 8.827A 8.963A 2.976A 549.506 84.205% 1787 40 39.03°C 0.995
Row 20 – Cell 0 11.966V 5.097V 3.312V 5.038V 652.59 Row 20 – Cell 6 Row 20 – Cell 7 Row 20 – Cell 8 49.11°C 114.7V
110% 42.351A 9.81A 10.054A 2.979A 604.507 82.601% 1892 41.5 40.07°C 0.99
Row 22 – Cell 0 11.953V 5.096V 3.31V 5.035V 731.86 Row 22 – Cell 6 Row 22 – Cell 7 Row 22 – Cell 8 51.01°C 114.69V
CL1 0.114A 14.098A 14.35A 0A 121.259 82.457% 0 <6.0 44.05°C 0.982
Row 24 – Cell 0 12.090V 5.121V 3.323V 5.093V 147.058 Row 24 – Cell 6 Row 24 – Cell 7 Row 24 – Cell 8 38.63°C 114.82V
CL2 0.113A 19.483A 0A 0A 101.373 81.471% 0 <6.0 42.96°C 0.979
Row 26 – Cell 0 12.116V 5.132V 3.325V 5.098V 124.431 Row 26 – Cell 6 Row 26 – Cell 7 Row 26 – Cell 8 35.86°C 114.83V
CL3 0.113A 0A 24.802A 0A 83.86 75.11% 0 <6.0 44.03°C 0.977
Row 28 – Cell 0 12.103V 5.131V 3.326V 5.088V 111.653 Row 28 – Cell 6 Row 28 – Cell 7 Row 28 – Cell 8 34.91°C 114.82V
CL4 45.813A 0A 0A 0.001A 549.314 85.196% 1802 40.2 38.46°C 0.995
Row 30 – Cell 0 11.990V 5.115V 3.321V 5.085V 644.764 Row 30 – Cell 6 Row 30 – Cell 7 Row 30 – Cell 8 49.37°C 114.71V

The PSU doesn’t have a problem delivering full load and even more at high operating temperatures. Efficiency gets a big hit, though. 

20-80W Load Tests

In the following tests, we measure the PSU’s efficiency at loads significantly lower than 10% of its maximum capacity (the lowest load the 80 PLUS standard measures). This is important for representing when a PC is idle with power-saving features turned on.

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Test 12V 5V 3.3V 5VSB DC/AC (Watts) Efficiency Fan Speed (RPM) PSU Noise (dB[A]) Temps (In/Out) PF/AC Volts
20W 1.225A 0.488A 0.495A 0.196A 19.985 73.95% 0 <6.0 36.25°C 0.864
Row 2 – Cell 0 12.110V 5.121V 3.333V 5.108V 27.025 Row 2 – Cell 6 Row 2 – Cell 7 Row 2 – Cell 8 33.2°C 114.85V
40W 2.698A 0.683A 0.693A 0.294A 39.985 82.785% 0 <6.0 36.58°C 0.931
Row 4 – Cell 0 12.108V 5.122V 3.333V 5.106V 48.3 Row 4 – Cell 6 Row 4 – Cell 7 Row 4 – Cell 8 33.24°C 114.84V
60W 4.174A 0.878A 0.891A 0.392A 59.984 85.909% 0 <6.0 37.83°C 0.956
Row 6 – Cell 0 12.103V 5.122V 3.332V 5.103V 69.824 Row 6 – Cell 6 Row 6 – Cell 7 Row 6 – Cell 8 34.05°C 114.84V
80W 5.645A 1.074A 1.089A 0.49A 79.923 87.472% 0 <6.0 38.7°C 0.968
Row 8 – Cell 0 12.098V 5.121V 3.332V 5.101V 91.37 Row 8 – Cell 6 Row 8 – Cell 7 Row 8 – Cell 8 34.72°C 114.83V

The fan doesn’t spin at light loads. 

2% or 10W Load Test

From July 2020, the ATX spec requires 70% and higher efficiency with 115V input. The applied load is only 10W for PSUs with 500W and lower capacities, while for stronger units, we dial 2% of their max-rated capacity.

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12V 5V 3.3V 5VSB DC/AC (Watts) Efficiency Fan Speed (RPM) PSU Noise (dB[A]) Temps (In/Out) PF/AC Volts
0.734A 0.211A 0.264A 0.048A 11.076 62.671% 0 <6.0 24.39°C 0.787
Row 2 – Cell 0 12.078V 5.114V 3.331V 5.113V 17.673 Row 2 – Cell 6 Row 2 – Cell 7 22.93°C 114.84V

The 60% mark is passed with a 2 % load. 

Efficiency & Power Factor

Next, we plotted a chart showing the PSU’s efficiency at low loads and loads from 10 to 110% of its maximum rated capacity. The higher a PSU’s efficiency, the less energy goes wasted, leading to a reduced carbon footprint and lower electricity bills. The same goes for Power Factor.

The platform is efficient, especially with 230V input, which is why it has a Silver rating in the Cybenetics scheme. 

5VSB Efficiency

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Test # 5VSB DC/AC (Watts) Efficiency PF/AC Volts
1 0.1A 0.511W 72.813% 0.064
Row 2 – Cell 0 5.112V 0.702W Row 2 – Cell 3 114.87V
2 0.25A 1.277W 77.809% 0.14
Row 4 – Cell 0 5.11V 1.641W Row 4 – Cell 3 114.88V
3 0.55A 2.807W 79.824% 0.246
Row 6 – Cell 0 5.106V 3.517W Row 6 – Cell 3 114.88V
4 1A 5.098W 80.257% 0.325
Row 8 – Cell 0 5.099V 6.353W Row 8 – Cell 3 114.88V
5 1.5A 7.637W 78.897% 0.373
Row 10 – Cell 0 5.092V 9.679W Row 10 – Cell 3 114.88V
6 2.999A 15.19W 77.812% 0.433
Row 12 – Cell 0 5.065V 19.523W Row 12 – Cell 3 114.87V

The 5VSB rail achieves decent efficiency. 

Power Consumption In Idle And Standby

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Mode 12V 5V 3.3V 5VSB Watts PF/AC Volts
Idle 12.060V 5.104V 3.327V 5.115V 6.071 0.45
Row 2 – Cell 0 Row 2 – Cell 1 Row 2 – Cell 2 Row 2 – Cell 3 Row 2 – Cell 4 Row 2 – Cell 5 114.84V
Standby Row 3 – Cell 1 Row 3 – Cell 2 Row 3 – Cell 3 Row 3 – Cell 4 0.054 0.006
Row 4 – Cell 0 Row 4 – Cell 1 Row 4 – Cell 2 Row 4 – Cell 3 Row 4 – Cell 4 Row 4 – Cell 5 114.84V

Vampire power is low with 115V input, but we would like to see below 0.1W with 230V input. 

Fan RPM, Delta Temperature, And Output Noise

All results are obtained between an ambient temperature of 37 to 47 degrees Celsius (98.6 to 116.6 degrees Fahrenheit).

(Image credit: Tom’s Hardware)

(Image credit: Tom’s Hardware)

The fan speed profile doesn’t seem aggressive at harsh conditions. 

The following results were obtained at 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit) ambient temperature.       

(Image credit: Tom’s Hardware)

(Image credit: Tom’s Hardware)

At normal operating temperatures, close to 30 degrees Celsius, the PSU’s semi-passive operation doesn’t last long if you push hard the minor rails. There is also a region where the fan spins, even with a minimal load on the minor rails. With more than 160W, noise exceeds 25 dBA, and with more than 300W, the 30 dBA mark is passed. Lastly, with higher than 360W noise is within the 35-40 dBA region. 

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Protection Features

Check out our PSUs 101 article to learn more about PSU protection features.

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OCP (Cold @ 26°C) 12V: 63.4A (138.43%), 11.921V
5V: 36A (180%), 5.106V
3.3V: 39A (156%), 3.321V
5VSB: 4.8A (160%), 5.030V
OCP (Hot @ 37°C) 12V: 63A (137.55%), 11.948V
5V: 36A (180%), 5.119V
3.3V: 39A (156%), 3.322V
5VSB: 4.8A (160%), 5.028V
OPP (Cold @ 26°C) 732.52W (133.19%)
OPP (Hot @ 37°C) 660.41W (120.07%)
OTP ✓ (110°C @ 12V Heat Sink)
SCP 12V to Earth: ✓
5V to Earth: ✓
3.3V to Earth: ✓
5VSB to Earth: ✓
-12V to Earth: ✓
PWR_OK Accurate but lower than 16ms
SIP Surge: MOV
Inrush: NTC Thermistor

The OCP triggering points are set high on all rails, especially the minor ones. Great Wall ignored setting up the minor rails properly. Who needs so many amps on them? On the contrary, the over power protection is set correctly.

DC Power Sequencing

According to Intel’s most recent Power Supply Design Guide (revision 1.4), the +12V and 5V outputs must be equal to or greater than the 3.3V rail at all times. Unfortunately, Intel doesn’t mention why it is so important to always keep the 3.3V rail’s voltage lower than the levels of the other two outputs.

No problems here since the 3.3V rail is always lower than the other two. 

Cross Load Tests

To generate the following charts, we set our loaders to auto mode through custom-made software before trying more than 25,000 possible load combinations with the +12V, 5V, and 3.3V rails. The deviations in each of the charts below are calculated by taking the nominal values of the rails (12V, 5V, and 3.3V) as point zero. The ambient temperature during testing was between 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit).

Load Regulation Charts

Efficiency Graph

(Image credit: Tom’s Hardware)

Ripple Graphs

The lower the power supply’s ripple, the more stable the system will be and less stress will also be applied to its components.

Infrared Images

We apply a half-load for 10 minutes with the PSU’s top cover and cooling fan removed before taking photos with a modified Fluke Ti480 PRO camera able to deliver an IR resolution of 640×480 (307,200 pixels).

We didn’t notice any high temperature spots inside the PSU, during this test session. 

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Advanced Transient Response Tests

For details about our transient response testing, please click here.

In the real world, power supplies are always working with loads that change. It’s of immense importance, then, for the PSU to keep its rails within the ATX specification’s defined ranges. The smaller the deviations, the more stable your PC will be with less stress applied to its components. 

We should note that the ATX spec requires capacitive loading during the transient rests, but in our methodology, we also choose to apply a worst case scenario with no additional capacitance on the rails. 

Advanced Transient Response at 20% – 20ms

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Voltage Before After Change Pass/Fail
12V 12.054V 11.618V 3.62% Pass
5V 5.105V 4.899V 4.04% Pass
3.3V 3.324V 3.126V 5.95% Fail
5VSB 5.091V 5.011V 1.57% Pass

Advanced Transient Response at 20% – 10ms

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Voltage Before After Change Pass/Fail
12V 12.059V 11.599V 3.81% Pass
5V 5.108V 4.903V 4.02% Pass
3.3V 3.325V 3.128V 5.92% Fail
5VSB 5.090V 5.014V 1.50% Pass

Advanced Transient Response at 20% – 1ms

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Voltage Before After Change Pass/Fail
12V 12.068V 11.629V 3.64% Pass
5V 5.113V 4.906V 4.04% Pass
3.3V 3.327V 3.109V 6.56% Fail
5VSB 5.090V 4.998V 1.81% Pass

Advanced Transient Response at 50% – 20ms

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Voltage Before After Change Pass/Fail
12V 12.011V 11.756V 2.12% Pass
5V 5.100V 4.924V 3.45% Pass
3.3V 3.319V 3.112V 6.22% Fail
5VSB 5.076V 5.002V 1.46% Pass

Advanced Transient Response at 50% – 10ms

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Voltage Before After Change Pass/Fail
12V 12.023V 11.746V 2.30% Pass
5V 5.106V 4.894V 4.16% Pass
3.3V 3.321V 3.117V 6.15% Fail
5VSB 5.075V 4.991V 1.66% Pass

Advanced Transient Response at 50% – 1ms

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Voltage Before After Change Pass/Fail
12V 12.023V 11.759V 2.19% Pass
5V 5.105V 4.932V 3.39% Pass
3.3V 3.321V 3.115V 6.21% Fail
5VSB 5.075V 4.981V 1.84% Pass

Transient response is mediocre on all rails but 5VSB, where it doesn’t matter so much. 

Turn-On Transient Tests

In the next set of tests, we measure the PSU’s response in simpler transient load scenarios—during its power-on phase. Ideally, we don’t want to see any voltage overshoots or spikes since those put a lot of stress on the DC-DC converters of installed components.

There is a huge voltage drop in the “PSU OFF To Full 12V” test, showing that something is off with the resonant controller’s programming. 

Power Supply Timing Tests

There are several signals generated by the power supply, which need to be within specified, by the ATX spec, ranges. If they are not, there can be compatibility issues with other system parts, especially mainboards. From year 2020, the PSU’s Power-on time (T1) has to be lower than 150ms and the PWR_OK delay (T3) from 100 to 150ms, to be compatible with the Alternative Sleep Mode.

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PSU Timings Table
T1 (Power-on time) & T3 (PWR_OK delay)
Load T1 T3
20% 36ms 129ms
100% 36ms 128ms

The PWR_OK delay is within the 100-150ms region, so the PSU supports the alternative sleep mode recommended by the ATX spec.

Ripple Measurements

Ripple represents the AC fluctuations (periodic) and noise (random) found in the PSU’s DC rails. This phenomenon significantly decreases the capacitors’ lifespan because it causes them to run hotter. A 10-degree Celsius increase can cut into a cap’s useful life by 50%. Ripple also plays an important role in overall system stability, especially when overclocking is involved.

The ripple limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V, and 5VSB).

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Test 12V 5V 3.3V 5VSB Pass/Fail
10% Load 53.0 mV 11.1 mV 9.0 mV 40.1 mV Pass
20% Load 30.5 mV 8.3 mV 8.8 mV 12.5 mV Pass
30% Load 24.4 mV 9.8 mV 9.0 mV 17.2 mV Pass
40% Load 45.0 mV 11.4 mV 9.8 mV 36.7 mV Pass
50% Load 40.9 mV 13.5 mV 10.7 mV 42.1 mV Pass
60% Load 36.0 mV 14.2 mV 10.4 mV 37.7 mV Pass
70% Load 41.2 mV 13.6 mV 10.9 mV 40.0 mV Pass
80% Load 20.9 mV 13.2 mV 12.7 mV 23.0 mV Pass
90% Load 39.0 mV 15.3 mV 13.0 mV 44.4 mV Pass
100% Load 33.3 mV 19.6 mV 15.7 mV 31.9 mV Pass
110% Load 38.8 mV 18.5 mV 16.1 mV 32.5 mV Pass
Crossload 1 33.5 mV 16.2 mV 15.6 mV 14.1 mV Pass
Crossload 2 27.8 mV 12.9 mV 8.9 mV 11.7 mV Pass
Crossload 3 44.7 mV 10.4 mV 16.8 mV 34.9 mV Pass
Crossload 4 32.5 mV 15.6 mV 12.1 mV 25.2 mV Pass

Ripple suppression is good on all major rails. The 5VSB needs a better filtering cap. 

Ripple At Full Load

Ripple At 110% Load

Ripple At Cross-Load 1

Ripple At Cross-Load 4

EMC Pre-Compliance Testing – Average & Quasi-Peak EMI Detector Results

Electromagnetic Compatibility (EMC) is the ability of a device to operate properly in its environment without disrupting the proper operation of other nearby devices.

Electromagnetic Interference (EMI) stands for the electromagnetic energy a device emits, and it can cause problems in other nearby devices if too high. For example, it can cause increased static noise in your headphones or/and speakers.

΅We use TekBox’s EMCview to conduct our EMC pre-compliance testing.

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A single spur exceeds the limits of the average and peak EMI detectors. Conducted EMI is low in all other frequencies. 

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Performance Rating

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The TUF 550 achieves high performance, but despite its modern platform, is cannot take the lead from the Corsair, XPG, and Thermaltake units that use less advanced platforms, all provided by Channel Well Technology. 

Noise Rating

The graph below depicts the cooling fan’s average noise over the PSU’s operating range, with an ambient temperature between 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit).

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Under normal operating temperatures, the average noise output is low for the standards of this category, but the CX550M puts it to shame, along with all other similar spec PSUs. 

Efficiency Rating

The following graph shows the PSU’s average efficiency throughout its operating range with an ambient temperature close to 30 degrees Celsius.

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We expected that this platform would achieve first place in this chart. The CX550M is not far behind, though. 

Power Factor Rating

The following graphs show the PSU’s average power factor reading throughout its operating range with an ambient temperature close to 30 degrees Celsius and 115V/230V voltage input. 

The APFC converter does a decent job with 115V but needs tuning for higher PF readings with 230V. 

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Corsair decided to withdraw its popular CX line because it was expensive to make while it addressed budget-oriented users. ASUS saw an opportunity there, grabbed the CX platform from Great Wall, and used it in its TUF Gaming PSUs. 

The problem is that they were forced to use inferior components compared to the CX units to keep the cost down, which affected performance. The cost of electronic parts has hugely increased in the last years, primarily because of the pandemic, so it is not easy to use quality parts in budget PSUs. 

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The TUF 550 achieves good overall performance, which could be even higher with more tuning and changes in its design. Great Wall has to proceed with some changes at some point if it wants to keep up with the competition. Although this is the most modern platform in the low-cost category, it still cannot surpass, in overall performance, the less advanced CWT CSB platform used in the XPG Pylon 550, the Corsair CX550M, and the Thermaltake Smart BM2 550. 

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Disclaimer: Aris Mpitziopoulos is Tom’s Hardware’s PSU reviewer. He is also the Chief Testing Engineer of Cybenetics and developed the Cybenetics certification methodologies apart from his role on Tom’s Hardware. Neither Tom’s Hardware nor its parent company, Future PLC, are financially involved with Cybenetics. Aris does not perform the actual certifications for Cybenetics.

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