Cougar Gex X2 1000w review

[dirtyferret]

thread is open to everyone just tagging some people
@Shrek
@Bill_Bright
@Bobaganoosh

So a few weeks ago we were talking about PSU temp ratings and Tom's recently posted a review of the 40c rated 80 plus Gold Cougar Gex X2 1000w. Just a few notes on this particular unit from the review

1) OEM is Huizhou Xinhuiyuan Tech (they make the CM MWE V2 line) yet Cougar is a sub of HEC. Cougar has used other OEMs like Sirfa so it's not unprecedented but still.
2) the 80 plus gold label on the box is metallic making it look like 80 plus titanium

3) in the hot box test at 45c this unit does not pass gold efficiency and it doesn't take too much to get a gaming PC to hit 45c+ internally


During hot testing, the Cougar GEX X2 1000W PSU experiences a colossal decrease in efficiency under heavy loads, with efficiency figures dropping to 87.6% at 115 VAC and 89.1% at 230 VAC, compared to 90.2% and 91.8% during cold testing. An efficiency degradation of more than 2.5% is unexpected for a quality unit, even if the platform is rated at 40°C. Closer observation reveals that the efficiency drop is significantly greater when the unit is heavily loaded, suggesting thermal stress of the unit’s active components.

Luckily for any user the rails remain in spec for hot box testing but for $170 this unit is 1) over priced and 2) may not be a gold unit @ 40c, definitely not at 45c

I think some bridge rectifiers were run without heatsink to improve their efficiency

so Aris reviewed it last year when it had a seven year warranty, efficiency was better but still not where you want it on a $170 unitbut check out the platform pics by Fylladitakis . What's with the fuzz around the plastic shielding. Who's doing QC at XHY?

 

[Shrek]

Random graph (Corsair AX860)

2% variation with load seems typical; more for a supply less efficient than the AX860, so I'd say this is par for the course.

Makes me happy to have my supply sit around 50% load.

 

[dirtyferret]

2% variation with load seems typical

that's input variation where you expect 230v to be higher than 110v. I'm talking about temp variation at equal input, specifically 45c 115v that pulls the unit below 80 plus gold.

 

[Shrek]

I meant the variation from top to bottom (~2% for either 110V or 220V in the AX860 example)

Fan takes ~5W, so that could be part of it (fan works harder during hot tests), but some cases have a separate box for the supply and then it does not matter so much that it is a gaming PC.

 

[Bobaganoosh]

so Aris reviewed it last year when it had a seven year warranty, efficiency was better but still not where you wan it but check out the platform pics by Fylladitakis . What's with the fuzz around the plastic shielding. Who's doing QC at XHY?

Eh, there's fuzz, lint, and thermal grease everywhere, but that does happen lol. Sure, it'd be nice if it didn't, but I couldn't look at pictures like that and assume it was the manufacturer over whoever disassembled it. Fibers like that tend to get drawn to things from static electricity and it's a pain to keep a whole workplace clean (just takes one person wearing their "ugly holiday sweater" on the production floor and it's a mess. Thermal grease on the other hand...that takes a lot of careful handling and training to keep nice. I struggle with that where I work constantly. People are not careful, and sometimes it's hard to see just how much has traveled to where it doesn't belong. An example: we had an LED board that was operated for several hours to increase stability of the LEDs, then it was supposed to be cleaned up before being installed. We then received a picture of the thing from our customer showing thermal grease and even what appears to be a feather on the board....where the hell a feather came from I have no idea...and the customer was in a clean-room...so to say I was livid about our handling of the board would be an understatement lol.

To be fair to scale here, some of the LED positions were unused so those are just solder blobs shorting the unused pads (which will always look a little ugly) and the LEDs themselves (example) in this case are approximately 1.7mmx1.3mm in dimension...so yes they're very small. My point is, look at all the grease and fuzz on there. It was completely unacceptable, but if you just looked at them with the naked eye it was hard to tell for most people. So training with magnification was helpful.

Looking at the power supply pictures...I wouldn't be happy about the grease being everywhere because that has a tendency to collect dust and particulates with it (which may create leakage current paths (see damaged LED above for example). The only fuzz I could see in the pictures looked like it came from either paper towels or Q-tips, which are often used to clean things in manufacturing. You'd want them to use something like kimwipes because they reduce lint, but the q-tips will still get you sometimes. It does look like they got grease in a lot of areas they shouldn't have though.


As for the efficiency issue, it could mean several things...the primary one is that they have some very temperature sensitive parts that have voltage drift with temperature and that increased voltage across that part becomes waste-heat. You usually get around that by either finding less sensitive parts or sometimes it's as simple as derating parts so that they don't see enough power to heat up much, even in a higher ambient temperature. That's often one factor that causes the efficiency to drop at higher loads, because the temperature of the parts increases, then the values shift, then there's more power lost to heat, etc. So again, the way to get around that is to spec. parts that don't waste enough power to drop below the efficiency rating. It would seem that this manufacturer did not do that.

 

[Shrek]

Can't say I am thrilled with the skewed heatsinks

 

[dirtyferret]

but that does happen lol. Sure, it'd be nice if it didn't, but I couldn't look at pictures like that and assume it was the manufacturer over whoever disassembled it.

Can't say I am thrilled with the skewed heatsinks

I caught that as well, I'll be nice and say the reviewer may have done it...

 

[Shrek]

Aris noted it:

"The PCB is tiny, and I cannot say I like the look of the non-straight pair of heatsinks."

 

[Bobaganoosh]

I think I looked at the pictures on the other review lol.

Is that tape around the transformers? If so, the edge there is likely sticky and picks up whatever dust and crap goes near it (that wasn't already picked up by the thermal grease and shmoo all around). This image in particular looked like q-tip fibers:

 

[Bill_Bright]

the 80 plus gold label on the box is metallic making it look like 80 plus titanium

Not sure the point of this. Pretty sure the color or type of ink used is not specified in the 80 PLUS display agreements. I've seen many Bronze certified look like Gold, but still say Bronze.

3) in the hot box test at 45c this unit does not pass gold efficiency

Ummm, yes it does - just barely. Note it is "80 PLUS" Gold certified - and NOT "80 PLUS 230V EU" certified. That matters because then you go by the 115V Internal and 230V Internal criteria which states 87% efficiency at 20% load and 88% efficiency at 20% load respectively. The Hot Test graph on Tom's clearly shows well above 88% efficiency for both voltages at 200W (20%) load.

Plus, the 80 PLUS testing criteria say,

5.6 Test Room As is specified in IEC 62301, the tests shall be carried out in a room that has an air speed close to the UUT of ≤ 0.5 m/s, and the ambient temperature shall be maintained at 23°C ± 5°C throughout the test.5.6 Test Room As is specified in IEC 62301, the tests shall be carried out in a room that has an air speed close to the UUT of ≤ 0.5 m/s, and the ambient temperature shall be maintained at 23°C ± 5°C throughout the test.

23°C ± 5°C is significantly lower than 45°C. Point being, nothing in the testing criteria says anything about 45°C.

Tom's also notes its compact size for a 1000W unit. Right or wrong, I almost always associate compact size with challenged cooling.

I am not saying this is a stellar PSU. But I have seen a lot worse.