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 can 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, 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. We even had three more oscilloscopes (Rigol VS5042, Stingray DS1M12, and a second Picoscope 3424), and a CEM DT-8852 sound level meter at our disposal. You will find more details about our equipment and the review methodology we follow in this article. 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 of 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 undervoltage threshold, or after the mains power has been removed for a sufficiently long time to guarantee that the PSU cannot operate anymore.



This PSU's hold-up time easily surpassed the 16 ms threshold, and we were very pleased to see so. The Hitachi bulk caps proved to have enough capacity to cover the needs of this unit under even full load.

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.



Inrush current was increased for a unit with 700 W capacity, but won't pose a problem, though we would like to get a reading below 40 A here.

Voltage Regulation and Efficiency Measurements

The first set of tests revealed the stability of the voltage rails and the efficiency of the Vector P700. 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.


With a deviation close to 1%, voltage regulation was tight enough on the +12V rail was tight enough, while deviation on all other rails was within 3%, which is more than decent. The unit also had no problems delivering its full power at very high operating temperatures, proving Xigmatek's claim for full power output at even 50°C. The CL1 test even shows the unit passing Intel's Haswell compatibility test successfully, though it is difficult. But our CL2 test didn't go as well since we experienced shutdowns once we dialed over 675 W load at +12V. The OCP probably triggered, although everything went smoothly during the overload test where +12V delivered around 680 W, but 675 W are still very close to the 696 W Xigmatek claims its +12V rail to produce on paper, so we really don't have much to complain about. This unit's fan profile proved to be rather relaxed and only during the CL2 test did it make the fan operate at full speed.

I asked for a second sample because of strange coil-whine issues at low loads. Once the second sample arrived, I discovered that it also suffered from the same problem. The PSU emits enough coil whine at 115-150 W to often be annoying since specific watt values (i.e. 125 W and 148 W) create clearly audible, highly pitched whine. This is obviously a design fault that should be fixed as soon as possible.