ocaholic - PSUs > Chieftec A135 Series APS-850CB Review

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Preview

Page 2 - Preview

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Delivery and Specifications

Delivery
Cable	Length
1 x ATX 20+4 pin	50 cm
1 x EPS/ATX 12V 8 & 4+4 pin	55 cm
4 x PCI-E 6+2 pin	55 cm
3 x 3 SATA	45, 60, 75 cm
1 x 3 Molex + FDD	45, 60, 75, 90 cm

The delivery of the APS-850CB is adequate. Since this is an 80Plus Bronze certified 850 Watt power supply, Chieftec is targeting the entry to mid-range DIY segment. The partially modular power management make perfect sense and apart from that it's a reasonable descision to ship this unit with a total of four PCI-E 6+2 Pin cables, which allows for connecting two graphics cards.

With this power supply Chieftec is offering a dual rail design regarding 12V. In total you get 80A, which can be turned into heat by the graphics cards for instance.

Specifications (according to Chieftec)
Voltage	Current	Power
+ 3.3 V	25 A	150 Watt	850 Watt (Total)
+ 5.0 V	25 A	150 Watt
+ 12 V1	40 A	850 Watt
+ 12 V2	40 A	850 Watt
- 12 V	0.3 A	3.6 Watt
+ 5 Vsb	3.0 A	15 Watt

The APS-850CB has been 80Plus Bronze certified. This means, that the efficiency of this PSU should be above 81% at 20% load, above 85% at 50% load and above 81% at 100% load.

At this point the feature list:

80Plus Bronze
OVP, UVP, OCP, SCP, OPP, OTP
Dimensions (W x H x D): 150 mm x 87 mm x 155 mm
135 millimeter fan
Warranty: 2 Years
Price: ~110 CHF / ~93 Euro

Page 3 - Delivery / Specs

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A Look Inside

Chieftec equipped this power supply with a well made and good looking case. A closer look at the fan reveals that it's a model from Global Fan with a simple ball bearing. As soon as we remove the lid, we see that Chieftec is using a DC-DC platform from High Power for this particular unit.

First things first: the transient filtering stage, comes with two X and four Y capacitors right behind the AC receptacle. On the main PCB there is a c CM02X chip, which helps discharging filter caps and therefore positively improves standby power consumption.

Continuing we find two parallel rectifiers, which are GBU805. Next to those we find the APFC module, which has been equipped with two Infineon 6R070C6 transistors as well as one Schottky diode (CREE C3D08060). We were rather surprised to find a large aluminum profile taking care of their cooling. If we're looking for the APFC controller chip we find a CM6800TX, which is a usual suspect in todays power supplies. Furthermore there is one APFC capacitor with 470uF capacity at 400V and up to 85°C. This is a taiwanese capacitor and this part of the APS-850CB is certainly not over-engineered. Moving on we find the half-bridge converter, which is based on two Infineon 20N60C3 CMOS transistors, which are also being cooled by the APFC cooling element.

Meanwhile we’ve arrive on the secondary side and here we find a dual rail design. All MOSFETs taking care of generating the two 12V rails are on two small and vertically mounted daughter PCBs. On each of these PCBs there are four AOT480 MOSFETs. Filtering on the secondary side is being handled by polymer capacitors, which has a positive effect on reliability and endurance of this unit. Furthermore there is another daughter PCB, which hosts the connectors for the cable management. Apart from that we again find polymer capacitors from Kuan Kun. The voltage regulation chips, which generate 3.3V and 5V have been place on this daughter PCB as well, which helps reducing power losses.

Last but not least a few words about soldering quality. With this particular unit Chieftec's OEM High Power is making sure, the soldering quality matches is suprisingly good for a unit with this price point.

Page 4 - A Look Inside

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Result Analysis and Discussion

Efficiency
Load	Pin(W)	Pout(W)	Efficiency
10 %	107.70	87.75	81.47 %
20 %	202.20	175.03	86.56 %
50 %	494.60	435.13	87.98 %
100 %	1028.80	865.46	84.12 %

The 80Plus Bronze certification requirements (81% - 85% - 81%) are surpassed especially at 20% Load. The full Load efficiency is a bit higher at 230V AC. This is the case with most of todays PSU's an it mainly originates from the reason of lower losses in the AC filtering stage and the PFC at 230V AC.

Output Stability
Load	Rail	Loading(A)	Output(V)
10 %	3.3V	1.5	3.4
	5V	1.5	5.2
	12V	5.9	12.3

20 %	3.3V	3.0	3.4
	5V	3.0	5.2
	12V	11.9	12.3

50 %	3.3V	7.5	3.3
	5V	7.5	5.1
	12V	29.6	12.3

100 %	3.3V	15	3.3
	5V	15	5.1
	12V	59.1	12.3

The Voltage Regulation of this PSU is very good. It makes use of a DC-DC topology. This means, that the APS-850CB is mainly a 12V PSU and then generates its 5 and 3.3V from 12V. This is a modern approach, and since the Load is mainly on 12V it makes a lot of sense. For almost any PSU which makes use of this topology crossload tests do not present a problem.

Noise
Load
20 %	silent
50 %	well audible

If we listen closer with this power supply, we hear a silent noise when the fan is at 20 percent load. At 50% the fan from Globe Fan with simple ball bearing is audible and at 100% it is well audible.

Noise/Ripple @ 100% Load
Voltage	Noise/Ripple Vpp
3.3V	0.028
5V	0.059
12V	0.064

The noise values are ok, but they are definitely not excellent. At 100% load we see that the ripple values range from 28mV to 64mV depending on the rail. Since the 12V ripple performance drastically improves with just little less 12V load, we don't judge this as a negative point.

Page 5 - Result Analysis and Discussion

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Conclusion

With the APS-850CB Chieftec released a solid mid-range power supply. The APS-850CB comes with an adequate delivery as well as a partially modular cable management as well as an 80PLUS Bronze certificate. Overall one can see that Chieftech has been saving money every here and there, which is understandable if a manufacturer wants to offer an 850 Watt PSU for quite a bit less than 100 Euro. There are for example only taiwanese capacitors and there is only one APFC filtering cap, which is definitely not too much for an 850 Watt PSU. Apart from that we would have loved to find a fan, that is a little less noisy. Should you be looking to build a well priced gaming PC, which you might want to upgrade with a second graphics card, then this unit is an overall reasonable choice. Chieftec offers two years warranty on this power supply which is actually below average. A closer look at the price reveals that it's on a competitive level since we find this unit over at Geizhals with prices starting from 93 Euro.

The Chieftec APS-850CB receives good 4 out of 5 stars.