ocaholic - PSUs > Chieftec Navitas 1250W GPM-1250C 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	55 cm
2 x EPS/ATX 12V 8 & 4+4 pin	55 cm
6 x PCI-E 6+2 pin	55 cm
4 x 3 SATA	55, 70, 85 cm
1 x 3 Molex	55, 70, 85 cm
1 x Floppy	15 cm

The delivery of the Navitas 1250W is adequate. Since PSUs with this kind of output power are often used for PCs with four or more graphics cards, it would have been nice if Chieftec added another pair of PCI-E 6+2 Pin cables, which can be connected to the EPS/ATX 12V 8Pin connector.

With this power supply Chieftec is offering a single rail design regarding 12V. In total you get 104A, 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	1'050 Watt (Total)
+ 5.0 V	25 A	150 Watt
+ 12 V	104 A	1248 Watt
- 12 V	0.8 A	9.6 Watt
+ 5 Vsb	4.0 A	20 Watt

The GPM-1250C has been 80Plus Gold certified. This means, that the efficiency of this PSU should be above 90% at 20% load, above 92% at 50% load and above 89% at 100% load.

At this point the feature list:

80Plus Gold
OVP, UVP, OCP, SCP, OPP, OTP
Dimensions (W x H x D): 150 mm x 86 mm x 200 mm
140 millimeter fan
Warranty: 2 Years
Price: ~204 CHF / ~170 Euro

Page 3 - Delivery / Specs

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A Look Inside

A very first solid hint for a high quality power supply can be when having a first look at its exterior. In this case we find a nice looking enclosure, which has been well manufactured. Apart from that there is a fan from Y.L. Tech which falls into the high-end category. Removing the top of this unit we quickly see that this PSU is based on CWTs PUO platform. One can tell this by the two green transformers. Despite the fact, that this isn’t the youngest platform it can still be considered state-of-the art. The reason for that is, that the primary side features loss-less LLC conversion as well as interleaved PFC circuitry and on the secondary side we find DC-DC conversion, which has been placed on a daughter PCB.

First things first: the transient filtering stage, comes with one X and two Y capacitors right behind the AC receptacle. On the main PCB there is a pair of Y caps, another pair of X caps, two CM chokes and one MOV. The transient filtering stage is therefore very well done and complete.

Continuing we find three parallel rectifiers, which are GBU 1006 and they can be loaded with up to 30A. As we already mentioned there is an interleaved PFC circuit, which actually means that there are two APFC converter working in parallel. In the case of the APFC converters we find IPW60R099CP MOSFETs as well as a CREE C3D 10060 diode. Next to the diode there is current sensing choke. Furthermore there are two large APFC capacitors from Nippon Chemi-Con, which feature 560uF capacity at 400V and they are specified for 105°C. In order to handle the interleaved PFC circuit, there is a UCC28070 controller and behind that there is the LLC converter, which is using four SiHG30N60E MOSFETs. Still on the primary side, we find a thermistor, which has been place right next to the two main transformers. Having the thermistor here makes perfect sense, since the transformers demand cooling.

Meanwhile we’ve arrive on the secondary side and here we find a synchronous design. All MOSFETs taking care of the 12V rail are on two small and vertically mounted daughter PCBs. On each of these PCBs there are six IPD031N06L MOSFETs. Filtering on the secondary side is being handled by polymer capacitors, which has a positive effect on reliability and endurance of this unit. A SITI PS229 chip is taking care of all the protection mechanism. Furthermore there is another large daughter PCB, which hosts the connectors for the cable management. Apart from that we again find polymer capacitors from Enesol and Duratech. Furthermore there are two inductors for additional filtering and rectification. The voltage regulation chips, which generate 3.3V and 5V have been place on this daughter PCB as well, which helps reducing power losses. In total there are four M300D and four M3006D MOSFETs taking care of this job and they are controlled via an APW7159 PWM controller.

Last but not least a few words about soldering quality. Chieftecs OEM (CWT) is making sure, the soldering quality matches the overall quality of this unit, which means it’s very well done.

Page 4 - A Look Inside

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Result Analysis and Discussion

Efficiency
Load	Pin(W)	Pout(W)	Efficiency
20 %	278.70	254.34	91.26 %
50 %	684.00	634.02	92.69 %
100 %	1393.00	1260.89	90.52 %

The 80Plus Gold certification requirements (87% - 90% - 87%) 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. The 230V AC 100% Load efficiency is 90.68%.

Output Stability
Load	Rail	Loading(A)	Output(V)
20 %	3.3V	3.2	3.3
	5V	3.2	5.1
	12V	18.3	12.2

50 %	3.3V	7.9	3.3
	5V	7.9	5.1
	12V	45.7	12.1

100 %	3.3V	15.7	3.3
	5V	15.7	5.1
	12V	91.2	12.1

The Voltage Regulation of this PSU is very good. It makes use of a DC-DC topology. This means, that the GPM-1250C 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 %	Noiseless
50 %	well audible

If we listen closer with the power supply, we don't here anything at 20 percent load. The GPM-1250C is a semi passive power supply and the fan kicks in, when 35 percent load is reached. It keeps spinning until the load goes below 25 percent. This ensures adequate internal temperatures under all circumstances. When demanding 50 percent load from this unit, the noise level can be described as silent and when there is 100 percent load, the unit is well audible.

Noise/Ripple @ 100% Load
Voltage	Noise/Ripple Vpp
3.3V	0.035
5V	0.033
12V	0.036

The noise values are ok, but they are definitely not excellent. At 100% load we see that the ripple values range from 30mV to 40mV no matter which voltages we're looking at. 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 GPM-1250C Chieftec released a high-end power supply. There is a costly AC filtering stage, a high end fan as well as excellent Nippon Chemi-Con capacitors, which - amongst other parts - add up to a great product. All the components mentioned comply with highest standards and its hard to find other PC PSU's which are built according to similar standards. Furthermore this PSU is very reliable even if you want it to deliver power 24/7. The Navitas 1250W is a very solid power supply and apart from that Chieftech is even selling at an attractive price point. We find this unit on Geizhals with prices starting at 169.90 Euro. The only thing we would really like to see changed is the warranty. Chieftech only offers two years of coverage. Other PSU vendors offer up to seven years warranty.

The Chieftec Navitas 1250W receives very good 4.5 out of 5 stars.