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Load Regulation, Hold-Up Time & Inrush Current

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

Corsair CX650M

Corsair TX750M

Corsair CX750M

Primary Rails And 5VSB Load Regulation

Load Regulation testing is detailed here.

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Hold-Up Time

Our hold-up time tests are described in detail here.

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The TX750M's hold-up time is lower than 17ms, and its power-good signal doesn't exceed 16ms like the ATX spec requires. At least the power-good signal is accurate, though.

Of the entire TX-M family, only Corsair's TX850M exceeds a 17ms hold-up time. Unfortunately, its power-good signal drops too early. In budget-oriented PSUs like these, smaller bulk caps are used to save money, inevitably leading to lower hold-up times than what we find from high-end PSUs. Regardless of price, though, every PSU is expected to satisfy the ATX specification if it's manufacturer claims compliance.

Inrush Current

For details on our inrush current testing, please click here.

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The inrush current is normal for a 750W unit.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the TX750M's efficiency. The applied load equals (approximately) 10 to 110 percent of the PSU's maximum load in increments of 10 percentage points.

We conducted two additional tests. During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.1A. This test reveals whether a PSU supports Intel's C6/C7 power states or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.

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Test #	12V	5V	3.3V	5VSB	DC/AC (Watts)	Efficiency	Fan Speed	Fan Noise	Temps (In/Out)	PF/AC Volts
1	4.402A	1.985A	1.982A	0.986A	74.794	84.959%	1250 RPM	29.8 dB(A)	38.74°C	0.988
12.088V	5.039V	3.329V	5.054V	88.035	40.59°C	115.12V
2	9.841A	2.971A	2.974A	1.186A	149.730	89.007%	1300 RPM	30.5 dB(A)	39.08°C	0.982
12.081V	5.036V	3.326V	5.049V	168.223	41.34°C	115.11V
3	15.640A	3.478A	3.486A	1.385A	224.895	90.406%	1395 RPM	31.2 dB(A)	39.63°C	0.989
12.073V	5.033V	3.323V	5.043V	248.760	42.16°C	115.11V
4	21.431A	3.975A	3.972A	1.587A	299.747	90.765%	1455 RPM	32.4 dB(A)	40.18°C	0.992
12.065V	5.030V	3.321V	5.038V	330.246	43.09°C	115.11V
5	26.896A	4.973A	4.972A	1.784A	374.736	90.595%	1545 RPM	34.2 dB(A)	40.92°C	0.994
12.056V	5.028V	3.318V	5.032V	413.641	44.37°C	115.11V
6	32.359A	5.973A	5.970A	1.987A	449.658	90.196%	1660 RPM	36.1 dB(A)	41.57°C	0.995
12.048V	5.024V	3.316V	5.028V	498.537	45.75°C	115.11V
7	37.839A	6.976A	6.971A	2.190A	524.660	89.619%	1730 RPM	37.4 dB(A)	42.21°C	0.996
12.039V	5.021V	3.313V	5.021V	585.434	46.88°C	115.10V
8	43.323A	7.972A	7.971A	2.391A	599.570	88.888%	1840 RPM	39.8 dB(A)	43.17°C	0.996
12.030V	5.019V	3.311V	5.015V	674.525	48.58°C	115.10V
9	49.248A	8.476A	8.488A	2.393A	674.653	88.108%	1840 RPM	39.8 dB(A)	44.20°C	0.997
12.022V	5.017V	3.308V	5.011V	765.713	50.41°C	115.10V
10	54.923A	8.981A	8.979A	3.000A	749.514	87.199%	1840 RPM	39.8 dB(A)	45.28°C	0.997
12.013V	5.014V	3.307V	5.000V	859.544	52.71°C	115.12V
11	61.198A	8.984A	8.984A	3.000A	824.393	86.357%	1840 RPM	39.8 dB(A)	46.55°C	0.995
12.005V	5.012V	3.305V	4.997V	954.631	55.15°C	115.11V
CL1	0.101A	16.027A	16.004A	0.004A	134.877	82.478%	1670 RPM	36.2 dB(A)	43.48°C	0.983
12.075V	5.025V	3.318V	5.058V	163.530	47.58°C	115.12V
CL2	62.451A	1.003A	1.003A	1.002A	763.756	87.870%	1840 RPM	39.8 dB(A)	45.23°C	0.997
12.015V	5.021V	3.316V	5.035V	869.185	51.93°C	115.11V

Our TX750M sample registers the best load regulation among all TX-Ms, especially on the minor and 5VSB rails. This is noteworthy, since normally the lowest-capacity models based on a given platform achieve superior load regulation. In this case, it's the second-strongest TX-M faring most admirably.

According to 80 PLUS, the TX750M satisfies its Gold level's requirements, even under high ambient temperatures. Corsair usually makes absolutely sure its specifications are accurate, and that's clearly the case here.

Despite ample efficiency, we're less satisfied by Corsair's fan profile under tough conditions. Even with less than 100W load, the fan spins at 1250 RPM, generating close to 30 dB(A). At least the TX750M's top speed is capped at 1840 RPM, keeping noise output under 40 dB(A). Still, we think the fan profile could be less aggressive. After all, this is an 80 PLUS Gold-rated PSU. We suspect that a long warranty has Corsair playing it safe in the temperature department.

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