Most recently, we tested a 650-watt power supply from the ASUS TUF Gaming series, today we got to test the older model of this line — TUF Gaming 750B. Let’s see what their differences are.
|Energy Efficiency Certificate||80 Plus Bronze|
|Cable Connection Diagram||Not removable|
|Channel power +12V, W (A)||744 (62)|
|Channel power +5V, W (A)||125 (25)|
|Channel power +3.3V, W (A)||82,5 (25)|
|Combined power +3.5V and +5V, W||130|
|Channel power -12, W (A)||9,6 (0,8)|
|Channel power +5Vsb, W (A)||15 (3)|
|Mains voltage range, V||100-240V|
|Mains voltage frequency, Hz||47–63|
|Fan size, mm||135x135x25|
|Number of cables/connectors for CPU||2/2x EPS12V (4+4)|
|Number of cables/connectors for PCI-E||2/2x (6+2)|
|Number of cables/connectors for SATA||2/8|
|Number of cables/connectors for IDE||1/4|
|protection||OPP, OVP, UVP, SCP, OСP, OTP|
|Dimensions (WxHxD), mm||150x86x150|
The design of the box is common for all models of the TUF Gaming line; on its sides there is all the necessary information about the characteristics of the device.
In addition to the unit itself, the package includes: two power cables with different plugs, a set of cable ties and fastening screws, a manual and a set of stickers.
Power supply with non-removable cables, their number and length are as follows:
- one to power the motherboard (60 cm);
- two with one 8-pin (4+4) connector (80 cm);
- two with two 8-pin (6+2) connectors for powering a PCI-E video card (60+12 cm);
- two with four power connectors for SATA devices (40+12+12+12 cm);
- one with four power connectors for IDE devices (40+15+15+15 cm).
All cables have black insulation and are covered with black braid, the wires are soft and long — the device should fit perfectly into large cases with a lower power supply.
Externally, the TUF-GAMING-750B case looks great: it is painted with black matte paint, the cooling fan is covered with a black protective grill, in its central part there is a large white TUF Gaming emblem. On the side faces there are black stickers with white inscriptions, plastic-based stickers and can be easily peeled off if anyone needs a stricter design.
The block is made on a common platform for all models of this line, which consists of an APFC with a wide supply voltage range, a power resonant LLC converter along the +12 V line with a synchronous rectifier. Separate DC/DC converters are responsible for powering the +3.3 V and +5 V lines.
A full-fledged surge noise filter is soldered on the input board, some of its elements are located on the network connector. Just like in the 650 W model, the starting current at the input is limited by the thermistor, next to which there is a place for installing a relay, but it is missing. The input rectifier consists of two GBU1508 diode assemblies connected in parallel. APFC is built on the CM6500UNX controller, which controls a pair of AP30SL60WL transistors (30 A 600 V) connected in parallel, the type of output diode could not be considered. After the corrector, the power is filtered by two electrolytic capacitors connected in parallel, with a capacity of 270 μF and a voltage of 450 V at 105 ° C of the LG series manufactured by TEAPO with a total capacity of 540 μF. Compared to the younger version of the power supply, we have more powerful transistors in the APFC and a larger high-voltage filter capacitance.
The resonant converter with a synchronous rectifier is made on the CM6901X controller. Power transistors are installed on the radiator along with APFC elements, their type could not be considered, four AP9990GP transistors (100A 60 V 0.006 Ohm) are installed at the output of the converter in the synchronous rectifier. The output voltage is filtered by a pair of 820 uF 16 V polymer capacitors and a pair of 2200 uF 16 V electrolytic Low ESR capacitors manufactured by Lelon RZW series.
The +3.3 V and +5 V lines are powered by a step-down DC / DC converter, assembled on a separate board, similar to that in the 650 W unit. A pair of chokes and two pairs of polymer capacitors for 470 uF 16 V and 1500 uF 6.3 V are installed on the board, two more Low ESR capacitors with a capacity of 2200 uF with a voltage of 10 V manufactured by Elite ED series are installed next to the board.
The standby power converter +5VSB is made on a TNY278PN PWM controller, its output is equipped with a polymer capacitor with a capacity of 820 uF 16 V and an electrolytic Low ESR capacitor with a capacity of 1500 uF with a voltage of 10 V manufactured by Elite of the ED series. An IN1S429I-DCG supervisor is installed nearby.
Mounting and soldering are of high quality, all components are installed evenly, the board is washed from the flux and the entire high-voltage part of the board is varnished.
The exact same fan as in the younger model is responsible for cooling the components — CF1325H12D (135x135x25 mm, 12 V and 0.6 A) manufactured by Champion with two ball bearings and a two-pin connection, the only difference is a plastic overlay to optimize airflow. The fan is controlled automatically with a semi-passive mode of operation, when the unit is started, the fan does not work and turns on at a power of more than 30% at 800–900 rpm, with an increase in the temperature of the temperature sensor installed on the radiator of the synchronous rectifier, the speed gradually increases to a maximum of 1800 rpm.
The test of the power supply was carried out using a linear electronic load with the following parameters: current adjustment ranges on the 3.3 V line 0-16 A, on the 5 V line 0-22 A, on the 12 V line 0-60 A, current and voltage measurement error stand 5%, all contacts for connecting cables of the tested power supply with the same voltage are connected in parallel and loaded with the corresponding load channel. The current for each channel is smoothly regulated and it is stable regardless of the output voltage of the unit. To accurately measure voltages, mains current and temperature, a Zotek ZT102 multimeter with True RMS was used. The fan speed was measured with a Uni-T UT372 tachometer. For each power line, the required current was set and the voltage at the load contacts was measured to take into account losses on the wires.
The first test for the load capacity of the main line + 12V, the current through the lines + 3.3V and + 5V was constant with a total load of about 130 W, the results are listed in the table.
|Load current on line +12V, A||Line voltage +12 V, V||Load power on line +12V, W||Line voltage + 5V at a current of 16 A||Load power on line +5V, W||Line voltage + 3.3V at a current of 15 A||Load power on line +3.3V, W||Total load power, W|
|Measurements on the contacts of the power supply|
According to the test results, we have excellent stabilization in all lines, as in the younger model. Additionally, a measurement was made on an unloaded SATA cable to obtain the output voltage on the power supply board at maximum load without taking into account the resistance of the wires. The wires turned out to be of quite high quality and the total losses on them are 17 W, you can also see the excellent work of the voltage drop compensation circuit on the wires, which increases the voltage at the outputs of the unit with increasing load so that the voltage does not sink much.
To check the load capacity of the +5V and +3.3V lines, tests were made at a constant load of +12 V to assess their influence on each other.
|Load current on the line + 3.3V, A||Line voltage +3.3 V, V||Load current on the line + 5V, A||Line voltage +5V, V||Load current on line +12V, A||Line voltage +12V, V|
According to the test results, we have excellent stabilization along the + 3.3V and + 5V lines, load distortions have almost no effect on each other and on the + 12V line.
The unit efficiency test was carried out at a mains voltage of 230 V.
|Load power, %||Load power, W||Consumed network current, A||Mains voltage, V||Efficiency, %|
The efficiency of this unit fully complies with the 80 Plus Bronze standard.
The heating test of the block components was carried out at an air temperature of 21 °C in the room, using the Scythe Kaze Master Pro panel, the sensors of which were fixed on the main components of the block, a thermocouple from a Zotek ZT102 multimeter was fixed on the power transformer, the block was loaded at maximum power and worked until the temperature of the power transformer has stabilized. The Scythe panel readings were recorded, after which the block cover was removed and the temperatures of the remaining components were measured. The results are shown on the following photo of the block board:
Element temperatures typical of modern power supplies with similar circuitry are slightly higher than the 650 W version, but then the test was at a lower room temperature, which allowed for a slight improvement in the overall cooling of the components by 2-3 degrees. With a long maximum load, the fan speed increased to 1700 rpm, while the noise from it was lower than that of the other fans of the test bench.
The tested ASUS TUF-GAMING-750B is a well-assembled modern power supply with a good design and good parameters. The power elements in it are installed with a margin, although the capacitors are not Japanese, they are of sufficient quality for a “bronze” block. Thanks to good circuitry like that of “golden” devices and with not very high heating, the unit will normally serve its warranty period of 6 years, even at powers close to the maximum, of course, with normal case ventilation. The unit’s disadvantages include a higher price than other bronze solutions, but the TUF-GAMING-750B is still closer to the «gold» ones, both in terms of circuitry and output voltage stability. Some may not like the lack of modularity, since after assembling the PC, there are quite a lot of extra wires and they will somehow need to be neatly arranged. The 750 W version is more preferable than the 650 W version discussed earlier, as it has more headroom for power components at a not very big difference in price. Like the younger model, it will be of interest, first of all, to fans of ASUS products.