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 Picoscope 3424 oscilloscope, a Picotech TC-08 thermocouple data logger, a Fluke 175 multimeter, 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 four more oscilloscopes (Rigol 1052E and VS5042, Stingray DS1M12, and a second Picoscope 3424), and a CEM DT-8852 sound level meter. In this article, you will find more details about our equipment and the review methodology we follow. Finally, we conduct all of our tests at 40°C-45°C ambient in order to simulate with higher accuracy the environment seen inside a typical system, 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 spec 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 under voltage threshold, or after the mains power has been removed for a sufficiently long time to guarantee that the PSU cannot operate anymore.



The hold-up time we measured wasn't among the lowest we have ever seen, though it was still below the minimum allowed time set by the ATX spec, so the PSU failed 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.



The small bulk cap lead to equally low inrush current. We would still prefer a higher capacity bulk cap, although the latter could cause increased inrush current.

Voltage Regulation and Efficiency Measurements

The first set of tests revealed the stability of the voltage rails and the efficiency of the 600B. 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 stayed within 3% and was nothing exceptional since only the 5V rail managed to get close to 1%. Based on a plain platform because cost reduction is the primary goal, the PSU gave us the efficiency numbers we were expecting from a Bronze unit. The really good point here is that the unit managed to deliver its full power at even very high operating temperatures while featuring a significantly quieter operation because of its more relaxed fan profile; that is, compared to its smaller brother, the 500B. We actually expect it to be the other way around, with the lower-capacity PSU producing less noise, but EVGA surprised us this time around. However, they might have improved all of their Bronze series units since it has almost been three months since our 500B review.

The results of the CL1 test clearly show that the unit cannot cope with Intel's extreme requirements for Haswell compatibility. We know that Intel's engineers for reasons unknown to us chose a rather extreme scenario, but hey are Intel and know what they are doing and saying, right? We can't pass them up since they set the rules of the game (ATX spec) and nor can PSU manufacturers. The only thing we have to note here is that EVGA says their Bronze series units to be fully compatible with Haswell CPUs since they tested these units extensively with real systems.