This man wants to know how well a power supply is able to perform when the heat comes on. But the boy inside the man wants chaos and destruction. Fortunately, I have the perfect solution - my hot box. This is a modified ATX case that sits on top of the SM-268 and gets all the heat from said load tester ducted and convected into it. Why, I've seen ambient temperatures in there hit insane numbers no currently available power supply is rated to.
Still, I do have to retain some semblance of fairness here, so I will try to keep the unit below its fifty degree maximum operating temp rating by turning on the exhaust and intake fans in the hot box. That should keep me from the lunatic fringe long enough to get this done.
Results from XFX XPS-850W-BES HOT load tests
Test #
+3.3V
+5V
+12V
DC Watts/
AC Watts
Eff.
Intake/
Exhaust
Simulated system load tests
Test
1
2A
2A
12A
171W/
194W
88.1%
27°C/
30°C
3.38V
5.14V
12.18V
Test
2
4A
4A
25A
348W/
388W
89.7%
31°C/
37°C
3.38V
5.13V
12.15V
Test
3
6A
6A
37A
512W/
581W
88.1%
34°C/
43°C
3.38V
5.12V
12.12V
Test
4
8A
8A
50A
686W/
792W
86.6%
37°C/
49°C
3.37V
5.11V
12.08V
Test
5
10A
10A
62A
848W/
995W
85.2%
41°C/
60°C
3.36V
5.10V
12.04V
Test
CL1
18A
18A
1A
172W/
208W
82.7%
34°C/
42°C
3.37V
5.09V
12.17V
Test
CL2
0A
0A
70A
851W/
990W
86.0%
39°C/
57°C
3.38V
5.14V
12.05V
It may be a mad, mad world outside this lab, but in here the XFX is chugging along like it's not even warm. Sure, the exhaust temperature is a toasty sixty-one degrees by test five, but look at those voltage readings... stable like the unit was made out of concrete. 3.3V and 5V are still inside 1% regulation. 12V is barely outside 1%. And the efficiency has actually gone up in test two, now flirting with 90%!
Did I hear the fan yet? No, I did not. It just wasn't speeding up to audible levels for anything.
Oscilloscope Measurements - XFX XPS-850W-BES
Test #
+3.3V
+5V
+12V
Test
1
Test
2
Test
3
Test
4
Test
5
Test
CL1
Test
CL2
Sweet Jeebus! Ok, I think we can say XFX is dead serious about taking over the market now. 12V ripple under 25mV. 3.3V and 5V barely active enough to get a reading at all. These results put the XFX into an elite group occupied by the likes of the Antec CP-850, Antec SG-850, PC Power & Cooling Silencer 910, and... yes... the Corsair HX850. It's really, really, really hard to get better ripple suppression than this, people.
