AcBel Polytech iPower 660 Power Supply Review

Load Tests

We conducted several tests with this power supply, as described in the article Hardware Secrets Power Supply Test Methodology.

First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its 610 W maximum capacity (actual percentage used listed under “% Max Load”) – and not 660 W –, watching how the reviewed unit behaved under each load. In the table below we list the load patterns we used and the results for each load.

If you add all the power listed for each test, you may find a different value than what is posted under “Total” below. Since each output can vary slightly (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. On the “Total” row we are using the real amount of power being delivered, as measured by our load tester.

+12V2 is the second +12V input from our load tester and during our tests we connected the two power supply ATX12V connectors to it. So it was connected to the power supply +12V2 bus. The +12V1 input from our load tester, on the other hand, was connected to both +12V1 (main motherboard connector and peripheral connectors) and +12V3 (video card power plug) rails.

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12V1	4.5 A (54 W)	9.5 A (114 W)	14 A (168 W)	18 A (216 W)	23 A (276 W)
+12V2	4.5 A (54 W)	9 A (108 W)	14 A (168 W)	18 A (216 W)	22 A (264 W)
+5V	1 A (5 W)	2 A (10 W)	4 A (20 W)	6 A (30 W)	8 A (40 W)
+3.3 V	1 A (3.3 W)	2 A (6.6 W)	4 A (13.2 W)	6 A (19.8 W)	8 A (26.4 W)
+5VSB	1 A (5 W)	1 A (5 W)	1.5 A (7.5 W)	2 A (10 W)	2.5 A (12.5 W)
-12 V	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)
Total	126.9 W	247.5 W	378.2 W	491. W	613.7 W
% Max Load	20.8%	40.6%	62.0%	80.5%	100.6%
Room Temp.	43.6° C	45.2° C	46.1° C	46.1° C	46.1° C
PSU Temp.	50.9° C	50.1° C	50.4° C	50.4° C	50.4° C
Voltage Stability	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	153 W	293 W	457 W	601 W	773 W
Efficiency	82.9%	84.5%	82.8%	81.7%	79.4%
Final Result	Pass	Pass	Fail	Fail	Fail

Just to remember, we are assuming that this is a 610 W power supply and we tested it as such.

The main problem with this power supply is that it can’t work continuously at a room temperature of 45° C. During our test number three the power supply shut down after 3 minutes, during test number four the power supply shut down after 10 seconds and during test number five the power supply shut down after 5 seconds. Well, at least it’s over power protection (OPP) was clearly in action.

iPower 660 is a textbook example of a power supply which was labeled at 25° C, which is a temperature impossible to be achieved inside a computer.

We also have seen that the rectifiers used on this power supply didn’t provide enough current for this unit to be able to deliver the unit’s labeled power, and our theoretical calculations proved to true.

We let our load tester and power supply cool down and turned them back on with pattern number four. The power supply could only stay on for two minutes – it shut down when the room temperature achieved 40° C.

So even though its power supply can in theory deliver up to 610 W, in practical terms this doesn’t happen. This unit can’t continuously deliver more than 350 W at a room temperature of 45° C.

Voltage regulation was  outstanding and during all our tests all outputs were within 3% of their nominal voltages – ATX specification defines that all outputs must be within 5% of their nominal voltages (10% for -12 V) –, including -12 V, which usually is not close to its nominal value.

Efficiency was good, but dropped below 80% during the five seconds we could run test number five.

Even though during all tests ripple and noise levels were within specs, they were almost touching the limit. With this power supply delivering 610 W noise level at +12V1 input from our load tester was at 98.9 mV, at +12V2 noise was at 95.2 mV, at +5 V it was at 25.8 mV and at +3.3 V it was at 15.2 mV.  Just to remember, all values are peak-to-peak voltages and the maximum allowed set by ATX standard is 120 mV for +12 V and 50 mV for +5 V and +3.3 V.

Figure 16: Noise at +12V1 input from load tester at 610 W.

Figure 17: Noise at +12V2 input from load tester at 610 W.

Figure 18: Noise at +5 V input from load tester at 610 W.

Figure 19: Noise at +3.3 V input from load tester at 610 W.

Over current protection (OCP) circuit was active and shutting down the power supply whenever we tried to pull
more than 21 A from any +12 V rail.

Short circuit protection (SCP) worked fine for both +5 V and +12 V lines.