be quiet! Straight Power 11 650W Platinum Power Supply Review

be quiet! Straight Power 11
(Image: © be quiet!)

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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.

The E11-PT-650 cannot meet most of the competing offerings in load regulation, in all rails. 

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.

Despite the low combined capacity bulk caps, the hold-up is longer than 20ms, meeting with ease the ATX spec's requirement. 

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.

The inrush current is low with 115V input, but this is not the case for 230V. 

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.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
13.582A1.976A1.971A1.000A64.96486.907%2367.0 40.17°C0.962
12.108V5.057V3.350V4.998V74.751 42.96°C115.11V
28.195A2.971A2.963A1.204A130.02990.725%2397.1 40.70°C0.972
12.096V5.049V3.342V4.983V143.322 44.02°C115.11V
313.158A3.469A3.464A1.409A195.04091.911%2407.1 41.25°C0.982
12.083V5.044V3.335V4.969V212.205 44.85°C115.11V
418.132A3.970A3.966A1.615A260.04992.228%2427.1 41.37°C0.987
12.070V5.037V3.328V4.954V281.963 45.90°C115.11V
522.772A4.972A4.969A1.823A325.09592.075%2457.2 42.36°C0.990
12.058V5.030V3.320V4.939V353.076 47.73°C115.11V
627.373A5.974A5.980A2.000A389.36991.005%47713.0 42.53°C0.992
12.045V5.023V3.312V4.924V427.853 48.50°C115.11V
732.057A6.982A6.995A2.243A454.84390.506%65316.3 43.21°C0.994
12.032V5.015V3.304V4.907V502.553 49.63°C115.11V
836.751A7.993A8.013A2.454A520.12990.010%77221.4 43.68°C0.995
12.019V5.006V3.295V4.891V577.858 51.08°C115.11V
941.861A8.502A8.515A2.458A585.05289.525%90523.4 44.37°C0.995
12.005V5.000V3.288V4.883V653.504 52.51°C115.10V
1046.717A9.017A9.056A3.093A649.90388.925%102627.3 45.52°C0.995
11.991V4.992V3.280V4.851V730.841 54.66°C115.10V
1152.184A9.027A9.072A3.097A714.73288.303%113730.7 46.84°C0.995
11.977V4.987V3.274V4.845V809.412 56.70°C115.10V
CL10.104A14.004A13.999A0.000A118.10684.674%553 14.5 42.27°C0.972
12.095V5.028V3.317V5.003V139.483 47.50°C115.12V
CL254.098A1.000A1.001A1.000A661.85189.694%1045 27.4 45.87°C0.995
11.989V5.016V3.304V4.946V737.900 54.52°C115.10V

Despite the high temperatures that we applied, the efficiency levels are in line with the 80 PLUS Platinum standard's requirements in the 20% and 50% load tests. With full load, it is very close to the 89% mark, with less than 0.1% difference. The power factor (PF) readings are also high, and this is important as well since lower amounts of energy go wasted, stressing less the distribution system.

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 #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts

The efficiency levels are satisfactory under light loads, and the PSU's fan is spinning at very low RPM, so it is practically inaudible.

2% or 10W Load Test

Intel plans on raising the ante at efficiency levels under ultra-light loads. So from July 2020, the ATX spec will require 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.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts

It would be nice to see over 70% efficiency with 2% load, but this is not the case, unfortunately. With a little more tuning, FSP could achieve this. 


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.

This is an efficient overall platform with the only problem being the performance with 2% load. 

5VSB Efficiency

Swipe to scroll horizontally
Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts

The 5VSB rail achieves satisfactory efficiency levels. The difference, though, with FSP's HPT650M unit, is chaotic. 

Power Consumption In Idle And Standby

Swipe to scroll horizontally
Mode12V5V3.3V5VSBWattsPF/AC Volts
Standby    0.142115.1V

The vampire power is increased with both voltage inputs. This dramatically affects the 5VSB rail's efficiency at light loads. 

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 profile is super relaxed, even under high operating temperatures. As we expected, be quiet! heavily focused on the PSU's quiet operation.

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 lower operating temperatures, the PSU's fan barely spins, so the noise output up to typical loads (around 50% of the PSU's max rated capacity) is minimal.

MORE: Best Power Supplies

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Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

  • emgarf
    Please consider providing sequencing and transient graphs for power-down as well as power-up. They are equally important.