XFX Black Edition 850w ATX PSU

Simulated Load Testing

Simulated Load Testing
To provide accurate and consistent results in all of our PSU testing, Overclock3D uses professional grade DC electronic load equipment capable of placing a sustained load of 3690w across a total of six rails (including +5vsb and -12v) on the PSU! This is achieved by using a combination of SunMoon and Analogic electronic load equipment which allow us to adjust amperage loads in increments as small as 0.01A while also measuring voltage and wattage readings on-screen.
During today's tests, we will be placing the XFX Black Edition under 25%, 50%, 75% and 100% load levels inside a hot box regulated to a temperature of around 50°C. Additional 'Cross Load' and a 'Max Load' tests will also be performed under these conditions to simulate how the PSU reacts to heavily uneven loads as well as running above its specified output.
XFX Black Edition 850w Results @ 50°C
   +3.3v  +5.0v  +12v  +5vSB  -12v  AC Watts /
 DC Watts
 Efficiency  Intake /
Δ Temp
Test 1
4.37A 4.37A 14.00A  0.75A  0.20A  242w /
 88.01% 50.4°C /
3.40v 5.12v 12.16v 5.00v  -12.05v
Test 2
8.75A 8.75A 28.00A 1.5A  0.40A  471w /
 90.23% 51.4°C /
12.10v 4.96v  -12.06v
Test 3
13.12A 13.12A 42.00A  2.25A  0.60A  705w /
 90.21%  49.5C /
3.38v 5.08v 12.06v 4.93v -12.11v
Test 4
17.50A 17.50A 56.00A 3.00A  0.80A 948w /
89.55%  51.0°C /
3.37v 5.07v 12.00v 4.89v -12.17v
Test 5
17.00A 16.00A 1.00A 0.00A 0.00A  182w /
82.96% 51.6°C /
-2.3 °C
3.39v 5.11v 12.14v 5.01v -12.60v
Test 6
 1.00A  1.00A  70.00A  0.00A 0.00A 939w /
90.52% 50.8°C /
3.40v 5.14v 12.02v 4.98v -14.33v
Test 7
 22.00A  22.00A 61.00A  4.00A  0.80A  ----w /
--.--%  --.--°C /
-.--v -.--v --.--v -.--v --.--v
XFX Black Edition 850w Performance Overview
 +3.3v Diff.
 +5.0v Diff.
 +12v Diff.
+5vSB Diff.
-12v Diff.
Avg Effic.
Noise Rating
0.88% 0.97% 1.31%  2.20%  0.99% 89.50% Low
Before we get to the big red part of the chart I first want to draw your attention to the standard tests 1-4. These best reproduce the kind of load that the PSU will receive when installed inside a PC. As we can see from the results and indeed the performance overview chart above, the XFX Black Edition 850w has some of the most stable rails I've ever seen in any PSU tested before on OC3D. The +3.3v and +5v rails are especially solid with less than a 1% drop in voltages from a low to full load which even bests our current favourite PSU, the Corsair HX850w. Efficiency was also extremely good with a high of 90.23% being seen at a 425w load in test 2 and an overall average of 89.50%.
However, all is not well. Part of OC3D's PSU testing procedure involves a "MAX Load" test in which the PSU is placed under a continually increasing load which takes it outside of its rated specification. This not only identifies the true capabilities of the PSU (for example if it is a 750w PSU overclocked to 850w, or a 1000w PSU underclocked to 850w) but also ensures that the OCP (Over Current Protection) is fully functional on the unit. Unfortunately this is where the XFX failed in a BIG way.
During this test the load was increased to 22A on both the +3.3v and +5v rails and 62A on the +12v rail. This combined with the small load on the +5vSB and -12v rail equated to around a 970w load on the PSU (120w above rated output). At first, everything appeared to be working fine. The ripple results were perfectly acceptable, the exhaust temperature was around 65°C and the voltages were all well within spec. Around a minute later the PSU powered off. Nothing unusual there, OCP had kicked in and saved the day. To find out whether the unit would be capable of sustaining a slightly lower load, the +12v rail load was reduced to 61A and the PSU powered back on. What happened next warranted a change of underwear...

An EXTREMELY loud BANG (heard even two floors down!) was emitted from the PSU accompanied by a bright flash. Yes, the XFX Black Edition had failed in a potentially dangerous way. Luckily none of the OC3D equipment was damaged by the elaborate death of the XFX PSU, but it is extremely worrying that the OCP protection on the PSU didn't kick in for a second time. Of course this could be put down to the unit being from a faulty batch, but as the unit tested in the video was the 2nd one to suffer this exact fate at the hands of our MAX LOAD tests, something does indeed seem wrong.
XFX Black Edition 850w Scope Results @ 50c
   +3.3v  +5.0v  +12v
Test 1
T1_3.3V T1_5V T1_12V
Test 2
t2_3.3v t2_5v t2_12v
Test 3
t3_3.3v t3_5v t3_12v
Test 4
t4_3v t4_5v t4_12v
Test 5
t5_3.3v t5_5v t5_12v
Test 6
t6_3.3v t6_5v t6_12v
Test 7

Finally we come to the +3.3v, +5v and +12v ripple results as recorded using a Rigol 25Mhz 400MSa/s oscilloscope during the load tests further up the page. Once again, the standard test 1-4 are exceptional with the ripple hitting a high of 30.4mV on the +3.3v rail, 22.4mV on the +5v rail and 36mV on the +12v rail. Even the cross-load results come back all-clear with a maximum ripple of 60.8mV on the +12v rail during test 6. Of course, the big let-down is once again Test 7 where I didn't have a chance to record any results before the unit met its untimely demise.
Now let's move on to the conclusion where I try to sum up everything seen today...     
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Most Recent Comments

12-10-2009, 13:05:28

Have to say that video is great for suspense! Rather shocking for such a big brand though. Be interesting to see if they say anything.

Still think that people will buy this no matter what just because it looks good and has XFX written on it.Quote

12-10-2009, 13:12:02

I Hunta x
ok is it just me or does the top of that psu look amazing?

the bang want that big in the video tho =\ i was expecting the camera to wobble and someone nearly cacking them self

other than that good review from the quick scim i gave it for now.Quote

12-10-2009, 13:42:09

Originally Posted by name='I Hunta x'

the bang want that big in the video tho =\ i was expecting the camera to wobble and someone nearly cacking them self
You can always turn up your volume for a more authentic reproduction. Unfortunately all the "cacking" was done when the first unit went bang right as I had my ear pressed against it while listening to the fan noise.Quote

12-10-2009, 15:27:57

Jim = Mr Calm.

Couple of cracks and he doesn't jump, flinch, move, gasp... nothing.

If BFG and XFX have taught us anything, and to a certain extent the woeful air performance on Corsairs 800D, it's that companies should stick to doing what they do best.Quote

12-10-2009, 15:54:34

Originally Posted by name='tinytomlogan'
Have to say that video is great for suspense! Rather shocking for such a big brand though. Be interesting to see if they say anything.

Still think that people will buy this no matter what just because it looks good and has XFX written on it.
And has high efficiency + good rippling as long as you don't let a madman with heavy testing equipment near it Quote

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