Cougar GX-F 750W PSU Review

1. Introduction2. Bundle & Cables3. External4. Internal5. Testing Methodology & Results6. Closing Thoughts7. View All Pages

Cougar have been in operation now for some time and for years have been releasing a plethora of cases, cooling products and power supplies for the mass enthusiast audience. As many of our readers already know, historically they haven't scored very well in our analysis – because I will be honest – for the most part, many of their power supplies haven't really been very good.

When I was offered the new GX-F range to review I can't say I was that excited, but taking a look at an HEC/Compucase OEM design felt long overdue – so here we are today.

Cougar are releasing three units in this new ‘high end' GX-F family, a 550W, 650W and 750W unit. They are all rated 80 Plus Gold and have ETA-A efficiency ratings. Cougar claim they can deliver full power output at 50c. These are all fully modular designs, which is great for cable routing in a new build.

Today we look at the flagship model in the small range of units – the 750W capacity unit. Cougar told us that the units ship with Hydro Dynamic Bearing fans with 150,000 hours of MTBF. Right now the range are available on Overclockers UK HERE. We can see that this 750 watt unit is available for £89.99 including VAT HERE.

It is a single rail design able to deliver 62 amps – we will look at this later in the review.

The Cougar GX-F 750 Watt at a Glance

• 750 Watt power supply with powerful 62 A single rail
• Very high efficiency thanks to 80 Plus Gold certification
• Quiet 135 mm fan with semi-passive mode
• Fully modular cable management
• Vier 6+2-Pin PCIe connectors for graphics cards
• Eight SATA connectors

Review photography handled in house at KitGuru with a Leica S series medium format camera and S series prime lens. Please do not use any of the images within this review without express permission.

The Cougar GX-7 arrives in a rather attractive looking box featuring a high resolution image of the unit on the front. We can see that this power supply is supported with a 7 year warranty and is 80 Plus Gold Certified.

The rear of the box goes into more detail explaining the compact nature of the unit itself, along with the fan and noise and efficiency curves.

Inside the box we have a user manual, general Cougar literature, a regional specific power plug, cable ties, mounting screws and the modular cables.

I was quite surprised to see only one EPS connector supplied with this supply – not such an issue with a 550W power supply, but with a 750W unit it seems like such a weakness. If you are sporting a powerful AMD Threadripper system this will likely put your off this model completely before we even get started on the testing. Other connectivity and cable length seems fine for a price conscious unit in this sector.

The unit is very compact and the overall design is quite simple with only a little red accenting on the branding. All of these are stickers incidentally and can be removed without a lot of effort – leaving a black box – if that suits your themed build better.

The large black fan is hidden behind a metal grill. We will take a closer look at it shortly when we open the supply.

One side of the power supply is home to the modular connector bay – all cleanly laid out in two rows and labelled for ease of installation.

The other side of the power supply has a vent to help with air flow, alongside a power connector and switch. The ‘Cougar' name is visible above the vent. Quite honestly, a little less branding with a bigger air flow vent here would have been a better move.

All of the Cougar stickers are easily removed. One of them was actually already starting to peel a little when I opened the box.

I was very surprised to see a 25A rating on both minor rails, for a total output of 150W. I would be expecting to see around 100W here as it would likely help the unit achieve a higher efficiency rating.  We don't want to excessively waste energy on the convertors for the minor rails.

The +12V rating of 62A is fine – as you would be able to power one or two graphics cards without any concerns.

Even though no one is likely to ever open their power supply (as it will void the warranty) Cougar are keen to showcase the ‘Hydro Dynamic Bearing Fan'. Life is rated at 150,000 hours. Its a 12V 0.33A rated fan made in China.

If you can't see the gallery of the power supply above, then you may need to whitelist us in your ad blocker as they can interfere with our display code.

This is a new platform from HEC and it features a proprietary transformer which is connected via bus bars to a daughtercard which incorporates the +12V FETs. This is a good way of doing it as the designers are able to reduce the energy losses sometimes inflicted with other designs. Soldering quality is a little disappointing and certainly not a patch on the high end units we have been reviewing lately from Seasonic.

HEC are using polymer capacitors for their ripple filtering stages although I did notice some cheap Chinese TEAPO SC caps.  The primary capacitor is a 1055c rated Japanese capacitor from Nippon Chemi Con – in their KMW series – rated 400v 680uF. Sadly the secondary caps are lower grade Taiwanese and Chinese brands. The HEC design does have UVP, SCP, OTP, OCP,. OVP and OPP which is good to see.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 35c) in our environment to greater reflect warmer internal chassis conditions.

We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
75W	0.95	3.33	0.93	5.00	5.13	12.23	0.50	5.02	0.20	-12.03
150W	1.65	3.32	1.66	4.98	10.61	12.20	1.00	5.02	0.20	-12.03
375W	3.00	3.31	3.02	4.96	28.11	12.18	1.50	5.01	0.30	-12.03
565W	4.05	3.31	4.07	4.93	42.94	12.11	2.00	5.01	0.30	-12.04
750W	4.90	3.29	5.24	4.90	57.48	12.02	2.50	5.00	0.50	-12.05

Load regulation seems to be fine, falling short of the best units we have tested recently, but still within acceptable parameters.

Cougar GX-F 750W Power Supply	Maximum Load
	775W

We managed to reach around 775W before the unit would shut down gracefully, after the protection kicked in. This is around 25 watts more than the rated output. Not the greatest result we have seen in recent years.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
734W	1.0	3.33	1.0	5.00	60.0	11.96	0.2	-12.03	0.50	5.02
154W	15.0	3.30	15.0	4.96	2.0	12.05	0.2	-12.03	0.50	5.01

The unit passes our Cross Load testing without any problems. When hit with 60 AMPS the +5V rail held at 4.96.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.

ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
75W	10	10	5	10
150W	10	10	5	15
375W	15	10	10	20
565W	20	15	10	25
750W	25	15	15	30

Noise suppression is surprisingly good – especially the +12V output, which peaked just under 15mV. We did however see the +3.3V and 5VSB rails hit 25mV and 30mV respectively. These are all still perfectly within the rated industry tolerance levels.

Efficiency (%)
75W	84.6
150W	90.4
375W	91.9
565W	91.4
750W	88.8

Power efficiency rates as pretty good for an 80 Plus Gold certified unit. At around 50% load it peaks around 92%, dropping to 88.8% at full load. We did record quite a low result at 50-75W load, below 84%.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the power supply we have taken it into our acoustics room environment and have set our Digital Sound Level Noise Decibel Meter Style 2 one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.

KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refrigerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
75W	30.2
150W	32.5
375W	33.3
565W	34.6
750W	35.7

The large fan seems to be spinning quite a bit due to whatever profile Cougar thought was ideal. At full load its clearly audible and I didn't particular like the pitch of the fan either. Quite irritating to my ears. Not sure why its quite so aggressive.

Temperature (c)
	Intake	Exhaust
75W	36	42
150W	38	46
375W	39	52
565W	45	57
750W	47	62

Cougar have set the fan profile up quite aggressively and while the noise levels are higher than I would have liked, the internal temperatures are held at very good levels.

Maximum load	Efficiency
775W	88.5

For those interested, we measured efficiency when stressing the unit to breaking point. 88.5 percent efficiency at 775W … hardly practical, but interesting regardless.

The Cougar GX-F 750W is a fairly solid unit, priced very competitively to target a large audience. The HEC design does nothing exceptionally well, but it also doesn't exhibit any glaring weaknesses that would cause concern. On an aesthetic level, I wasn't that impressed – its covered with stickers, one of which was peeling off at the corner when I opened the box. To be honest, I would remove all the stickers myself before putting it into a build. A plain black compact box is easy to hide.

The compact physical nature will appeal to many people – it will fit into the smallest of cases on the market today and the fully modular design will be ideal to keep a new system build as neat as possible.

Technically we didn't run into any major issues. Its quite loud under load thanks to a bizarre and frankly somewhat unnecessary aggressive fan profile that has been set for the unit. A little tweaking to this profile could have reduced noise yet provided enough air flow for the supply. Above a 400W load, the fan can be easily heard, so this is a little disappointing.

Load regulation falls within a parameter I would deem acceptable and ripple suppression is surprisingly good, especially the +12V  rail. Efficiency levels are pretty good considering the modest (by 2018 standards anyway) 80 Plus Gold certification.

It was great to see the HEC design incorporating a 105c rated Japanese primary capacitor, however the secondary stage adopts cheap Teapo SC capacitors, which raises a few concerns in regards to long term reliability for me.

Earlier in the review I mentioned that Cougar didn't adopt a secondary EPS connector for this 750W unit which seems a short sighted mistake to me. It will rule out any use for potential AMD Threadripper/Workstation uses and at this price, it would have been a solid option for system builders trying to keep costs down as much as possible.

You can buy the Cougar GX-F 750 watt power supply from Overclockers UK for £89.99 inc vat HERE. For another £12 you can get the Seasonic Focus Plus 750W 80 Plus Gold Modular power supply from Overclockers UK HERE.

Both supplies are fully modular, 80 Plus Gold rated and physically compact. That £12 extra ensures you aren't dealing with TEAPO capacitors in the secondary stage however, so for me it would have to be Seasonic, every time.

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Pros:

• Fully Modular.
• 105c Japanese primary stage capacitor.
• ripple suppression is great.
• competitively priced.

Cons:

• stickers galore, one of which was already coming away from the chassis.
• cheap TEAPO secondary stage capacitors.
• single EPS connector seems an oversight.
• Loud under load.
• Only £12 cheaper than the all Japanese Seasonic Focus Plus 750W Gold.

Kitguru says: This HEC design proves a solid enough power supply. If only they had decided to use good capacitors in the secondary stage instead of cheap Chinese TEAPO it would get a higher recommendation. £12 more gets you 100% Japanese Seasonic.

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