Test Setup

All measurements are performed utilizing a custom designed and built load tester, called Faganas, which is able to stress PSUs up to 1800 Watts. We also use a DS1M12 (Stingray) oscilloscope, a CHY 502 thermometer, a Fluke 175 multimeter and an Instek GPM-8212 power meter. Furthermore, in our setup we have included a wooden box, which along with a heating element is used as a Hot Box. Finally, we have at our disposal three electronic loads (Array 3711A, 300W), a Rigol 1052E oscilloscope and a CEM DT-8852 sound level meter. In the near future we plan to acquire six additional loads to complete our new test set up, which with the help of our custom built software will have the same capabilities with the, ultra expensive, Chroma ATEs.

Voltage Regulation Charts

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

Efficiency Chart

In the charts below you will find the efficiency of BW-B430JL and BW-B520JL + BW-B430JL linked at low loads and at loads equal to 20-100% of PSUs' maximum rated loads.

Voltage Regulation and Efficiency Measurements

The first set of tests reveals the stability of voltage rails and the efficiency of BW-B430JL. The applied load equals to (approximately) 20%, 40%, 50%, 60%, 80% and 100%, of the maximum load that the PSU can handle. In addition, we conduct two more tests. In the first we stress the two minor rails (5V & 3.3V) with the maximum load that our tester can apply to these rails, while the load at +12V is only 2A and in the second test we dial the maximum load that +12V can handle while load at minor rails is minimum.


Our hot box converted to an oven during the above tests and nearly baked the small BITWIN, but the latter still worked effortlessly even when we asked for more than its maximum rated capacity, Watts. Efficiency is definitely Bronze and with 40% load reaches its peak at 86.54%. Even at full load it remains above 85%. Very good efficiency levels for a plain Bronze PSU. The only downside is the voltage regulation in the Crossload 1 test where group regulation shows its weaknesses. Voltage at the 5V rail dropped below ATX limit and the +12V rail surpassed the corresponding limit. However the results in the Crossload 2 test are fairly good, since voltages are close to the nominal values defined by the ATX spec.

Voltage Regulation and Efficiency Measurements with two BITWINs Linked

For the following tests we linked a BW-B520JL with the BW-B430JL and applied loads equal to (approximately) 20%, 40%, 50%, 60%, 80% and 100%, of the maximum combined capacity of the two PSUs. Here we must note that Jou Jye suggests that you must use the PSU with the higher capacity as "Master PSU" and the one(s) with lower as "Slaves". The most important thing is that since BITWIN PSUs use group regulation you must apply a load to the 5V/3.3V rails of the Slave PSU, else the +12V rail will not work properly. So you must not connect the Slave PSU only to the VGAs via its PCIe connectors, but utilize also its peripheral ones and power storage, fans etc. Finally you must not use a PCIe of the Master PSU and one of the Slave PSU to power a VGA with two PCIe inputs. The PCIe connectors of each PSU must be connected to different VGAs, in other words do not mix the +12V rails of the PSUs together because you will have increased ripple that will shorten the life of your systems components (and their stability).

Briefly the connections you should make when you utilize Multi Link.
Master PSU: ATX 24 pin and EPS to the mainboard, PCIe connectors to VGA
Slave PSU: PCIe connectors to the other VGA, SATA and Molex to peripheral devices.
The ATX 24 pin connector of the Slave PSU remains unconnected.

In the following table 12 V1 denotes the 12V output of BW-B520JL and 12 V2 the corresponding of BW-B430JL



Jou Jye has a point here, indeed efficiency with two PSUs linked is high, at least for loads ranging from 20% to 100% of the combined maximum rated capacity.
We didn't notice any significant differences in voltage regulation of +12V and 3.3V rails but at 5V voltage regulation was improved since this was the only rail that we combined from the two PSUs (we didn't record any increase in ripple at the particular rail). Finally, the bad result we saw in the single PSU Crossload 1 test has not improved.

Efficiency at Low Loads

In the next tests, we measure the efficiency of BW-B430JL at loads much lower than 20% of its maximum rated load (the lowest load that the 80 Plus Standard measures). The loads that we dial are (approximately) 40, 65 and 90W. This is important for scenarios in which a typical office PC is in idle with power saving turned on.


We didn't have to run test 3 since this is equivalent to 20% load. Efficiency with only 42.24W load is above 75% and with 25W (approximately) more increases significantly and reaches 81%.

Efficiency at Low Loads with two BITWINs Linked

As we expected the Achilles' heel of the Multi Link feature is efficiency at low loads (below 20% of maximum rated capacity). Efficiency even with 91.5W load cannot reach 80%, so if you mostly run your system at such low load levels you better avoid linking two PSUs together.

Power Consumption in Idle & Standby

In the table below you will find the power consumption and the voltage values of all rails (except -12V), when the PSU is in idle mode (On but without any load at its rails) and the power consumption when the PSU is in standby (without any load at 5VSB).


Consumption at idle, strangely, is a tad higher than its bigger brother, BW-B520JL. But what matters most is consumption in standby mode or vampire power, the BW-B430JL clearly wins since it consumes only 0.15W. Thus not only meets the 2010 EuP (European Guideline on Energy using Products) requirements but it's also below the 0.5W limit that the upcoming 2013 EuP will set.

Power Consumption in Idle & Standby with two BITWINs Linked

Even with two BITWINs linked the consumption in standby mode is well bellow the 2010 EuP limit.