Cooler Master Silent Pro 700w Modular PSU
Load Testing
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To provide our readers with the most accurate results, Overclock3D uses a custom-built PSU load tester on all reviews. This not only gives much more reliable results than the testing methods employed by other sites, but also allows for all current and future review results to be compared side-by-side. The following table shows the load (in watts) that was applied to the Silent Pro 700w during testing.
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Compared to the results from the other rails seen below, the +3.3v rail seemed extremely solid and quite isolated from any load exerted on the +5v and +12v rails. This could possibly indicate that the smaller transformer pictured on the previous page is actually dedicated to the +3.3v rail, with the +12v and +5v rails sharing the larger transformer.
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Under normal circumstances, we’d discuss the performance of the +5v and +12v separately, but as we can see from the graphs above, the results from the two rails are in some way directly related to each other…
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With 0w load applied, the +12v rail is at a rather dangerous 12.95v, whereas the +5v rail is at the opposite end of the scale producing just 4.76v. Obviously no system is ever going to use 0w, so these results should not be taken into account when assessing the performance of the unit – but they are interesting never less.
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Placing a 10 amp load across all three rails to produce a total load of 203w, the +12v rail comes down to a much more reasonable (but still slightly high) 12.48v. This seemed to have a see-saw effect on the +5v rail, with the voltage actually increasing to 4.90v. The same was also exhibited when placing a further 10a load on the +12v rail (Total load: 323w), with the +5v rail rising to 5.00v and the +12v rail falling to 12.35v.
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Increasing the load to 20a on the +3.3v and +5v rails and 30a on the +12v rail saw the results swing back in the other direction. This time the voltage on the +12v rail increased to 12.39v while the +5v dropped sligtly to 4.97v.
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Applying additional load to the +12v rail in 10a increments up to a total of 50a (Total load: 766w) saw an expectable result of the +12v rail voltage dropping down to a minimum of 12.01v, but strangely, yet again the +5v rail increased up to 5.13v.
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Efficiency Results
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Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains (Mains Draw) against the power consumed by the OC3D power supply stress tester (PSU Load). These results may not be 100% accurate, but have proven to be extremely close to results obtained from professional equipment.
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Throughout the testing, the Silent Pro managed an efficiency level of at least 81.9%. Depending on the load applied to each of the PSU rails, this efficiency level went as high as 85.7% at times, reinforcing Cooler Master’s claims that the unit is able to achieve >85% efficiency.
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Temperature, Fan Speed & Noise
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As with all components in the modern computer system, the performance of a PSU can be directly affected by heat. Excess heat inside the PSU can easily have a negative effect of the maximum power output of the unit and lead to voltage instability. For this reason, Overclock3D includes temperature recordings taken from the PSU’s exhaust using a thermal probe to highlight any potential issues that the PSU might have obtaining its rated output.
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Under normal circumstances, we’d also use a sound meter to record the dBA noise level output by the fan. However, the Silent Pro certainly lives up to its name and was so quiet that it was almost impossible to take an accurate dB(A) reading from the PSU without ambient noise affecting the results. Even with the fan voltage hitting 7.02v when at 766w load, the noise emitted by the fan was too low to measure and could only be distinguished from the din of a nearby motorway by placing my ear within 30cm of the cooling fan.