Efficiency, Temperature And Noise
Efficiency
Our efficiency testing procedure is detailed here.
Using the results from the previous page, we plotted a chart showing the EVGA SuperNOVA 850 P2's efficiency under low loads, and loads from 10 to 110 percent of the PSU's maximum-rated capacity.
This is a highly efficient PSU throughout its load range; the graphs above clearly show this.
Efficiency At Low Loads
In the following tests, we measure the 850 P2's efficiency under loads significantly lower than 10 percent of its maximum capacity (the lowest load the 80 Plus standard measures). The loads we dialed were 20, 40, 60 and 80W. This is important for representing when a PC is idle, with power-saving features turned on.
| Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed (RPM) | Fan Noise | PF/AC Volts |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1.190A | 0.491A | 0.480A | 0.195A | 19.65 | 66.97% | 0 | 0 dB(A) | 0.836 |
| 12.251V | 5.054V | 3.324V | 5.113V | 29.34 | 115.1V | ||||
| 2 | 2.406A | 0.981A | 0.991A | 0.390A | 39.72 | 79.03% | 0 | 0 dB(A) | 0.892 |
| 12.253V | 5.052V | 3.323V | 5.104V | 50.26 | 115.1V | ||||
| 3 | 3.623A | 1.475A | 1.504A | 5.095A | 59.81 | 83.44% | 0 | 0 dB(A) | 0.915 |
| 12.253V | 5.049V | 3.321V | 5.095V | 71.68 | 115.1V | ||||
| 4 | 4.829A | 1.983A | 1.985A | 0.785A | 79.77 | 86.31% | 0 | 0 dB(A) | 0.934 |
| 12.254V | 5.048V | 3.320V | 5.087V | 92.42 | 115.1V |
With only 20W load, efficiency drops below 70 percent. However, with 40W of load it goes above 79 percent, and in the last two tests the unit easily passes the 80 percent mark. We would like to see greater than 70 percent efficiency in the first test, but obviously Super Flower's engineers preferred to tune this PSU for better efficiency at higher loads.
5VSB Efficiency
The ATX specification states that 5VSB standby supply efficiency should be as high as possible, recommending 50 percent or higher with 100mA of load, 60 percent or higher with 250mA of load and 70 percent or higher with 1A or more of load.
We take four measurements: one each at 100, 250 and 1000mA, and one with the full load the 5VSB rail can handle.
| Test # | 5VSB | DC/AC (Watts) | Efficiency | PF/AC Volts |
|---|---|---|---|---|
| 1 | 0.101A | 0.52 | 71.23% | 0.107 |
| 5.119V | 0.73 | 115.1V | ||
| 2 | 0.251A | 1.28 | 76.19% | 0.208 |
| 5.113V | 1.68 | 257.5V | ||
| 3 | 1.002A | 5.10 | 79.07% | 0.375 |
| 5.087V | 6.45 | 115.1V | ||
| 4 | 2.502A | 12.57 | 78.03% | 0.454 |
| 5.025V | 16.11 | 115.1V |
Efficiency at 5VSB isn't high enough, especially for a Platinum-rated PSU and taking into account the rail's low amperage.
Power Consumption In Idle And Standby
| Mode | 12V | 5V | 3.3V | 5VSB | Watts | PF/AC Volts |
|---|---|---|---|---|---|---|
| Idle | 12.268V | 5.053V | 3.326V | 5.121V | 8.79 | 0.630 |
| 115.1V | ||||||
| Standby | 0.10 | 0.015 | ||||
| 115.1V | ||||||
In the table above, you'll find the power consumption and voltage values of all rails (except -12V) when the PSU is idle (powered on, but without any load on its rails), and the power consumption when the PSU is in standby mode (without any load, at 5VSB).
Vampire power is very low, as usually is the case in modern PSUs equipped with dedicated standby PWM controllers.
Fan RPM, Delta Temperature And Output Noise
Our mixed noise testing is described in detail here.
The first chart below illustrates the cooling fan's speed (in RPM), and the delta between input and output temperature. The results were obtained at 37 °C (98.6 °F) to 49 °C (120.2 °F) ambient temperature.
The next chart shows the cooling fan's speed (again in RPM) and output noise. We measured acoustics from one meter away, inside a small, custom-made anechoic chamber with internals completely covered in sound-proofing material (be quiet! Noise Absorber kit). Background noise inside the chamber was below 18 dB(A) during testing, and the results were obtained with the PSU operating at 37 °C (98.6 °F) to 49 °C (120.2 °F) ambient temperature.
The following graph illustrates the fan's output noise over the PSU's entire operating range. The same conditions of the above graph apply to our measurements, though the ambient temperature was between at 28 °C (82.4 °F) to 30 °C (86 °F).
With ECO mode enabled and under normal operating conditions, the fan won't spin under loads of up to 340W. And even when it is engaged, it spins slowly. Expect low output noise as a result. In general, this is a very quiet PSU that'll satisfy enthusiasts who hate loud PC parts.
Scores a 9.7 on Jonnyguru, but is low end of tier 1 got it.
I like Tom's in general, been coming here since Tom was actually doing reviews, but I'll take JonnyGuru's(or Oklahoma Wolf) word that this is an awesome PSU, it scored 10 of 10's in all but Value, where a couple of similar quality PSU were a tad cheaper.
I've got the G2 model(thanks to their review of it) and couldn't be happier with it. Well other than they now have Platinum and Titanium versions and would prefer one of those. But 80+ Gold is still good enough for me.
Well, i think that you don't pay that much attention to Jonnyguru.com, as much as you claim.
Look here, at Jonny's tier list, and notice what tier is the EVGA's P2 line :
http://www.jonnyguru.com/forums/showthread.php?t=12947
The same reason so many regions have different plug types. They all designed these things before anyone had the idea to standardize these things across regions, and by now it's an incredible amount of work to have to redesign the infrastructure of entire countries.
Gotta hand it to the Americans for inventing the concept of the grid and power distribution to the masses, they did it first, and Edison's equipment at the time ran best on 110v so it was the obvious choice. Currently it's at 120v, this was changed in the 50s. Don't forget houses are supplied with 240v, this is what runs our hot water heaters, ovens and air conditioners. Just the old way is still too set in stone to be changed, not to mention 120v is safer for human exposure (a shock from a 120v outlet is much less dangerous than that of a 240v outlet, having experienced the 120v shock I can't imagine how painful a 240v would be)
Yep...I was popped by a 220v 3-prong washing machine plug wire that arced some two decades ago (when it was still known as a 220v power connection) and it knocked me on my butt. It makes getting hit by 120v (used to be 110v), which I've also experienced more recently, seem like carpet static electricity.
This is the summary for my EVGA 850 G2 (Tier 2 according to his list, a WIP according to the post)
It scores a 9.9 of 10, and is somehow a Tier 2 according to that list. I have no clue as to what he is doing with his list on the forums. I cannot explain HOW a unit that scores 9.9 of 10 is anything less than Tier 1. There are some Corsair units that scored perfect 10's that are also listed as Tier 2 on it as well.
If it's scoring that close to 10, or an actual 10 (his highest score), it's a Tier 1 to me. And I'd never second guess buying one regardless of brand.