Test Setup

All measurements were performed using two Chroma 6314A mainframes equipped with the following electronic loads: six 63123A [350 W each], one 63102A [100 W x2], and one 63101A [200 W]. The aforementioned equipment is able to deliver 2500 W of load, and all loads are controlled by a custom-made software. We also used a Rigol DS2072A oscilloscope kindly sponsored by Batronix, a Picoscope 3424 oscilloscope, a Picotech TC-08 thermocouple data logger, two Fluke multimeters (models 289 and 175), and a Yokogawa WT210 power meter. We also included a wooden box, which, along with some heating elements, was used as a hot box. Finally, we had at our disposal three more oscilloscopes (Rigol VS5042, Stingray DS1M12, and a second Picoscope 3424), and a CEM DT-8852 sound level meter. You will find more details about our equipment and the review methodology we follow in this article, Finally, we conduct all of our tests at 40°C-45°C ambient to simulate the environment seen inside a typical system with a higher accuracy, with 40°C-45°C being derived from a standard ambient assumption of 23°C and 17°C-22°C being added for the typical temperature rise within a system.

Primary Rails Voltage Regulation

The following charts show the voltage values of the main rails, recorded over a range from 60 W to the maximum specified load, and the deviation (in percent) for the same load range.

5VSB Regulation

The following chart shows how the 5VSB rail deals with the load we throw at it.

Hold-up Time

Hold-up time is a very important PSU characteristic and represents the amount of time, usually measured in milliseconds, a PSU can maintain output regulations as defined by the ATX spec without input power. In other words, it is the amount of time the system can continue to run without shutting down or rebooting during a power interruption. The ATX specification sets the minimum hold-up time to 16 ms with the maximum continuous output load. In the following screenshot, the blue line is the mains signal and the yellow line is the "Power Good" signal. The latter is de-asserted to a low state when any of the +12V, 5V, or 3.3V output voltages fall below the undervoltage threshold, or after the mains power has been removed for a sufficiently long time to guarantee that the PSU cannot operate anymore.



The measured hold-up time was too low, which means that a very low capacity bulk cap was used to restrict cost, and while it might have successfully lowered the final price, it also had the unit perform incredibly poorly in this test.

Inrush Current

Inrush current or switch-on surge refers to the maximum, instantaneous input-current drawn by an electrical device when first turned on. Because of the charging current of the APFC capacitor(s), PSUs produce large inrush-current right as they are turned on. Large inrush current can cause the tripping of circuit breakers and fuses and may 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.



As we expected, registered inrush current was very low because of the low hold-up time due to the low capacity bulk cap, which led to good results in this particular test.

Voltage Regulation and Efficiency Measurements

The first set of tests revealed the stability of the voltage rails and the efficiency of the ST60F-ESB. The applied load was equal to (approximately) 20%, 40%, 50%, 60%, 80%, 100%, and 110% of the maximum load the PSU can handle.

We conducted two additional tests. In the first test, we stressed the two minor rails (5V and 3.3V) with a high load while the load at +12V was only 0.10 A. This test reveals whether the PSU is Haswell ready or not. In the second test, we dialed the maximum load the +12V rail could handle while the load on the minor rails was minimal.

Voltage regulation on all rails was fairly good at normal loads since all deviations were within 2%. However, the group regulation scheme this unit utilizes clearly showed its weakness during our crossload tests, and the results of the CL1 test revealed that this PSU doesn't comply with Intel's Haswell requirements. This doesn't mean that powering a Haswell system with this unit will cause problems. However, while the ST60F-ESB doesn't meet Intel's requirements which are without a doubt really tough, Intel's engineers must know a thing or two more than the rest of us to put such rigorous specifications in place.

Although Silverstone only speaks of a maximum operating temperature of 40°C, the PSU had no problems delivering its full power and even more at close to 45°C ambient. However, fan speed quickly rose to 100% once the temperature inside the hotbox exceeded 40°C. Judging by the Delta difference between input and output temperature, we can't say that the fan did a great job, but the unit did manage to survive all of our tests. Finally, efficiency was typical to that of a Bronze unit using an older design.