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Load Regulation, Hold-Up Time & Inrush Current

To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units.

Aerocool ACP-850FP7

EVGA 850 B3

Thermaltake SPR-0850F-R

Primary Rails And 5VSB Load Regulation

Load Regulation testing is detailed here.

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Hold-Up Time

Our hold-up time tests are described in detail here.

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The hold-up time we observed is longer than 20ms, and the 850 B3's power-good signal is accurate.

Inrush Current

For details on our inrush current testing, please click here.

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The inrush current is normal for this unit's capacity.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the 850 B3's efficiency. The applied load equals (approximately) 10 to 110 percent of the PSU's maximum load in increments of 10 percentage points.

We conducted two additional tests. During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.1A. This test reveals whether a PSU is compatible with Intel's C6/C7 sleep states or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.

Test #	12V	5V	3.3V	5VSB	DC/AC (Watts)	Efficiency	Fan Speed (RPM)	Fan Noise (dB[A])	Temps (In/Out)	PF/AC Volts
1	5.210A	1.985A	1.991A	0.980A	84.785	80.878%	0	<6.0	43.15°C	0.954
1	12.128V	5.047V	3.310V	5.092V	104.831	80.878%	0	<6.0	38.55°C	115.18V
2	11.444A	2.971A	2.992A	1.181A	169.620	85.014%	0	<6.0	45.29°C	0.982
2	12.125V	5.041V	3.305V	5.076V	199.521	85.014%	0	<6.0	40.50°C	115.18V
3	18.052A	3.478A	3.510A	1.380A	254.853	86.712%	1218	27.3	41.24°C	0.989
3	12.119V	5.036V	3.300V	5.060V	293.906	86.712%	1218	27.3	46.13°C	115.19V
4	24.648A	3.977A	4.001A	1.584A	339.727	87.533%	1276	29.0	41.29°C	0.992
4	12.112V	5.032V	3.296V	5.045V	388.113	87.533%	1276	29.0	46.48°C	115.20V
5	30.912A	4.974A	5.009A	1.785A	424.624	87.466%	1338	30.7	41.63°C	0.994
5	12.104V	5.026V	3.292V	5.029V	485.473	87.466%	1338	30.7	46.95°C	115.22V
6	37.193A	5.977A	6.022A	1.994A	509.607	86.950%	1462	34.3	42.72°C	0.995
6	12.094V	5.021V	3.287V	5.010V	586.089	86.950%	1462	34.3	48.26°C	115.19V
7	43.502A	6.981A	7.038A	2.199A	594.560	86.345%	1600	36.1	43.47°C	0.996
7	12.079V	5.017V	3.282V	4.992V	688.583	86.345%	1600	36.1	49.30°C	115.20V
8	49.797A	7.987A	8.058A	2.410A	679.494	85.549%	1743	40.0	44.14°C	0.996
8	12.071V	5.010V	3.275V	4.975V	794.273	85.549%	1743	40.0	50.18°C	115.18V
9	56.545A	8.488A	8.583A	2.414A	764.493	84.596%	1885	42.2	44.62°C	0.996
9	12.060V	5.007V	3.271V	4.965V	903.702	84.596%	1885	42.2	50.88°C	115.18V
10	63.031A	9.005A	9.088A	3.036A	849.365	83.782%	1885	42.2	45.71°C	0.997
10	12.052V	5.002V	3.267V	4.935V	1013.785	83.782%	1885	42.2	52.33°C	115.18V
11	70.143A	9.016A	9.099A	3.042A	934.308	82.482%	2014	43.1	46.20°C	0.997
11	12.041V	4.997V	3.262V	4.925V	1132.742	82.482%	2014	43.1	53.15°C	115.18V
CL1	0.098A	14.023A	14.004A	0.004A	117.803	77.549%	1432	32.6	44.59°C	0.974
CL1	12.123V	5.027V	3.292V	5.107V	151.908	77.549%	1432	32.6	50.67°C	115.20V
CL2	70.778A	1.004A	1.003A	1.002A	865.942	83.783%	2003	43.0	47.16°C	0.996
CL2	12.046V	5.011V	3.278V	5.022V	1033.550	83.783%	2003	43.0	53.82°C	115.18V

Load regulation is pretty tight on every rail, particularly considering this PSU's price point. Better still, the 850 B3 delivers more than its full power at 46°C.

The registered efficiency levels are low though, especially under full load. And the fan speed profile is quite aggressive once the operating temperature and load increase. Of course, this is a low-efficiency PSU, so high fan speeds are expected; they help keep the internal temperature manageable. As a result, EVGA's 850 B3 easily satisfies the 80 PLUS Bronze requirements, even under high operating temperatures.

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Aris Mpitziopoulos

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

12 Comments Comment from the forums

orionfotl

There's a typo in the Final Analysis: "Although we're glad the 850 B3 didn't blow up like the 450W model, this is our second (so fat) B3-series power supply to die on the bench."
So fat.

Shame on the PSU.
Reply
Aris_Mp

(so far) Thanks!
Reply
Realist9

Part of what I got from this review and the associated charts is that my next psu will likely be a Corsair unit.
Reply
dstarr3

It seems like the general wisdom is still "Don't buy a PSU unless it has a 7- to 10-year warranty." The best products from the best OEMs always come with those warranties lately.
Reply
Aris_Mp

If you ask me the warranty isn't an indication from the moments it is 5 years long. On the other hand when a company avoids sending some specific PSUs for review, then the whole thing looks suspicious.
Reply
dstarr3

20217010 said:
If you ask me the warranty isn't an indication from the moments it is 5 years long. On the other hand when a company avoids sending some specific PSUs for review, then the whole thing looks suspicious.

I don't necessary mean that longer warranty = better product. I just mean that there are some OEMs that are better than the rest, and their best PSUs are the best on the market, and all those best PSUs happen to have 7- to 10-year warranties on them. So if you see that warranty on a PSU right now, you can reasonably assume that it is one of the best models from one of the best OEMs.
Reply
Olle P

I don't totally agree with the "Pros" and "Cons":
* Six 8-pin PCIe-connectors are supposed to be capable of delivering up to 900W. This PSU can't handle that.
* The efficiency is as advertised. That's neither a "Con" nor a "Pro". (In fact I'm impressed with the efficiency at 20W load. Expected worse.)
* Sleeve bearing is what makes the fan relatively quiet, so it's not a "Con" per se. Had it been a ball bearing fan you'd written "High noise level" as a "Con" instead.
Reply
Aris_Mp

Efficiency is a con in general. It is low

If the fan had DBB and an optimal fan profile then it wouldn't be a con. A sleeve bearing fan in a 100 buck PSU doesn't look good and those type of bearings are suited for horizontal installation so they should normally be avoided in PSUs.
Reply
obsidian86

Seasonic focus 850 currently for $10 more than this settles it
Reply
al3xand3r

Hi Aris, congratulations for the wonderful review and all of your work.
I've seen all of your reviews, but one thing I do not understand compared to other review sites and that's related to the advanced transient tests. For example, the be quiet! Pure Power 10 600W PSU, in Advanced Transient Test at +12V, 20% - 20ms has a voltage drop of 0.211V. At 50% load 20 ms is a voltage drop of 0.222 volts. Instead, at ardOCP, the same PSU records a 0.520 volt voltage drop at 20% load - 10 ms and 0.540 volts at 50% load – 10ms. And that's a huge difference. And I do not think this difference is because of the reduced time from 20ms to 10ms because at 1ms wich is tougher the drops it's not as high. What is wrong with ardOCP methodology?
Is it possible that a quality PSU like this to have a voltage drop in load so high (0.52 Volts)? And that's just an example. At all the PSU’s I've seen on both sites are differences like this. Same as when you were doing only 50ms or 200ms. Is there any explanation for these figures that do not coincide?
Thank you
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