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Three 1000 W 80 PLUS Gold-Certified Power Supplies Tested
By , Patrick Afschar,
1. Extreme Power For Extreme Users

It's easy enough to assume that 80 PLUS Gold-certified PSUs with power ratings in excess of 1000 W are not built with the broad masses in mind. It takes a serious configuration to require such high power delivery ceilings. Nevertheless, the findings in this roundup make it pretty clear how much importance the manufacturers attach to the quality of their products. Even the slightest deficiency is exposed immediately at such high loads, and the negative effects on energy efficiency are often quite severe. We received three PSUs for this piece, and we put them all through our gauntlet.

Compared to our recent roundup of gaming PSUs where the manufacturers almost buried us in test samples, the range of products is much more manageable in the high-end space. We're looking at two 1000 W PSUs from OCZ and Rosewill, along with a 1250 W PSU from Sparkle. Can the Sparkle PSU exploit its significant power rating advantage in any way? And how will these 80 PLUS Gold perform at the low loads typical of an idle PC?

Also Tested: Standby Power Consumption, EuP Standard

The European Union’s Eco-design Directive 2009/125/EC, also known as the EuP (short for Energy-using Product), contains increased stringency regarding the standby mode power consumption of PSUs from the year 2010. As more and more manufacturers are advertising the EuP certification on their PSUs, we are introducing the appropriate test methods in our reviews. Unlike previous standby measurements made with the 5 V-sb rail active, there are no loads on the rails in the EuP tests. The PSU must manage a standby power consumption of less than 1 W.

2. OCZ Z-Series Z1000M

The OCZ Z-Series Z1000M is part of the manufacturer’s Maximum Performance category. Not wasting any time on modesty, OCZ describes the 1000 W PSU as the perfect power supply for enthusiasts who want nothing but the best. The five-year warranty and fairly lofty price of $205 underline the company's perceived quality standards. To be fair, the OCZ PSU is the least-expensive in our comparison here.

The Z1000M's performance is impressive on paper. Its single 12 V rail can handle up to 83 A, sufficient for extremely power-hungry computers. The maximum power on the 12 V rail is 1000 W, according to the manufacturer, the same number as the PSU’s specified continuous output. That means that if the 12 V rail is fully utilized, the OCZ Z1000M is actually delivering more than 1000 W.

The PSU has a very high-quality finish and its brushed surface makes it a feast for the eyes. The cables are partly modular, with the ATX, PCIe, and some of the SATA cables being hard-wired to the PSU. The length and number of cables is unusually generous, including six PCIe and 12 SATA connections, though perhaps we would have expected more than three Molex connectors from a PSU in this category.

OCZ Z1000M
AC Input100-240 V, 50-60 Hz
DC Output+3.3 V+5 V+12 V (#1)+12 V (#2)+12 V (#3)+12 V (#4)-12 V+5 Vsb
25 A25 A83 An/an/an/a0.8 A6 A
Individual Output     9.6 W30 W
Rail UtilizationSysSysCPU & VGA
Combined Output180 W1000 W
Total Continuous Output1000 W
Peak Output1100 W


3. OCZ Z Series Z1000M: Measurements

Efficiency in accordance with the 80 PLUS specification

Efficiency, based on performance profiles

The part about expecting a bit more applies to the energy efficiency measurements as well: the OCZ Z1000M misses two of the 80 PLUS Gold certification minimum values in our tests. It is one percentage point short of the target at a 50% load, and two percentage points off at a 100% load.

The PSU performs quite well overall, though, particularly since its efficiency does not decrease very much at low loads. The ripple test values are outside the specification on the 3.3 V rail, though the standards are easily met on the 12 V and 5 V rails.

The PSU package sports an EuP-ready logo, and rightly so, according to our measurements. There are no abnormalities in the other tests. The temperature-controlled fan does its job very quietly and the temperature increase under load is a low 8°C. The fan also continues running for a while after turning off the computer.

The bottom line is looking quite good for the OCZ PSU and its single-rail design. It fulfills the highest standards when it comes to pure 12 V rail performance, though a slight hiccup in energy efficiency and ripple/noise have to be noted.

4. Rosewill Lightning-1000

Rosewill is celebrating its debut in our PSU roundups with the Lighting-1000. The Lighting-1000 is an 80 PLUS Gold-certified PSU with a 1000 W power rating, and its looks stand out from the competition. First, the modular cables are screwed in, instead of plugged in. This should counter some of the criticism that modular designs receive, given the fact that they add one additional failure point should a cable come loose. Second, it has LED lights. The user can choose between blue or red. Or, switch the lights off completely. The build quality is good, even if it does not feel quite as solid as the OCZ PSU. The sliding switch for the LED lights feels a bit cheap, too.

Rosewill only grants a three-year warranty, but in return the PSU costs a little less than OCZ's at $220, too. There is nothing to criticize in the way of cable count or their length. The modular cable parts come in a large case, fixed with rubber bands. The single 12 V rail is rated at a maximum of 83 A, just like the OCZ Z1000M.

Rosewill Lightning-1000
AC Input100-240 V, 47-63 Hz
DC Output+3.3 V+5 V+12 V (#1)+12 V (#2)+12 V (#3)+12 V (#4)-12 V+5 Vsb
25 A25 A83 An/an/an/a0.5 A3.0 A
Individual Output      6 W15 W
Rail UtilizationSysSysCPU & VGA
Combined Output120 W996 W
Total Continuous Output1000 W
Peak Output??? W


5. Rosewill Lightning-1000: Measurements

Efficiency in accordance with the 80 PLUS specification

Efficiency, based on performance profiles

The Rosewill Lightning-1000 leaves a mixed impression in our test lab. It misses the 80 PLUS Gold certification threshold by nearly two percentage points under full load, even if it hits the target at 50% and 20% load. The sharp fall of energy efficiency at low loads is striking, as the device achieves just 47% efficiency at a 25 W load. In other words, more than half of the power is wasted as heat, making the 80 PLUS Gold logo look quite out of place. However, in the defense of the PSU it should be mentioned that a 1000 W PSU is not intended for such low loads, and the efficiency is fine at 50 W and up.

The ripple/noise measurements are good, and the same goes for the other tests. The EuP standby power limit is not a problem, nor is the noise level.

The Rosewill Lightning-1000 deserves some criticism. It has some smart details and stands out from the crowd visually. But the missed 80 PLUS Gold threshold and the very sharp fall in efficiency at low loads dim the overall impression.

6. Sparkle GW-EPS1250DA

The Sparkle GW EPS1250DA differs from its competitors in several ways. It is the most expensive, to start, with a price of $300. It's also the most powerful, delivering up to 1250 W. And it has a total of six 12 V rails. The power connector uses the rather unusual C20 connector, facilitating up to 16 A of current, so be sure to not forget your cable when going to a LAN party. 

At first glance this all sounds quite reasonable, especially since the build quality and colors are convincing, if not for the fact that the power connector is rather loosely-connected to the PSU housing. Hopefully this is just a bad sample. Sparkle offers a five-year warranty, which is a redeeming point.

The length of the modular cables and number of connectors are more than sufficient, and three floppy connectors might actually almost be too many. The Sparkle GW-EPS1250DA has six 12 V rails, each rated at 20 A. The high number may very well mean that one will have a problem keeping track of the individual cables. Therefore, Sparkle prints color coded labels for the 12 V rails onto the unit.

However, this doesn't guarantee that the user will actually plug cables into the right places on the power supply, especially since all of the modular sockets have the same purple color. Therefore, there is a risk that one or two of the 12 V rails are under heavy load when the others aren't. We could not reach the theoretical maximum of 120 A over the six rails in our tests, since the voltage of the individual 12 V rails was already below the ATX specification limits at 113 A. Obviously, this PSU has no power reserves left.

Sparkle GW-EPS1250DA 
AC Input90-264 V, 50-60 Hz

DC Output+3.3 V+5 V+12 V (#1)+12 V (#2)+12 V (#3)+12 V (#4)+12 V (#5)+12 V (#6)-12 V+5 Vsb
30 A30 A20 A
20 A
20 A
20 A
20 A
20 A
0.6 A3.0 A
Individual Output       7.2 W15 W
Rail UtilizationSysSysCPU & VGA
Combined Output170 W1250 W
Total Continuous Output1250 W
Peak Output1440 W


7. Sparkle GW-EPS1250DA: Measurements

Efficiency in accordance with the 80 PLUS specification

Efficiency, based on performance profiles

The 1250 W Sparkle PSU fails rather badly in the 80 PLUS Gold certification tests: all limits are missed by one to two percentage points. Even taking measurement tolerances into account cannot explain such a result. In short, it cannot quite keep up with the two other competitors in the energy efficiency department. Its efficiency does not drop as much as the Rosewill Lightning-1000 at low loads, though. But then again, it just barely misses the EuP 1 W limit too.

The Sparkle GW EPS1250DA is a PSU that can talk the talk, but not quite walk the walk. Its high performance and interesting details, such as its C20 16 A power connector and multi-rail design, do not protect it from avoidable mistakes.

8. Test Configuration, Holdup-Time, Inrush Current, Peak, And Short Circuit Tests
Test Hardware
AC SourceChroma Programmable AC Source 6530
Power MeterYokogawa WT210 Digital Power Meter
Loads4 x 600 W Chroma 63306 for 12 V testing
4 x 300 W Chroma 63303 for 5 and 3.3 V testing
using Chroma HighSpeed- DC Load Mainframes 6334 
OscilloscopeTektronix DPO3034 Digital Phosphore Oscilloscope (300 MHz)
Test Procedure
Voltages110 and 230 V
Standby Power0.25 A fixed current to simulate PC standby power
on 5 Vsb
80 PLUS Efficiency Testing100/50/20% load, relative to specified total output
Load distribution across 12/5/3.3V rails at the same proportion as specified for 100%
testing at 110 V according to ATX 2.3 specification
Efficiency at Fixed Loads25, 50, 85, 300, 500 W loads
Load distribution across 12/5/3.3 V rails at the same proportion as specified for 100%
Peak Load Test110% Overload Testing at maximum combined 12 V
Temperature TestAir intake vs. Outtake temperature delta
tracking highest delta during all tests


Holdup-Time, Inrush Current, Peak And Shoirt Circuit Tests

Short Circuit Protection Test (12 V)
Model
Test Passed
OCZ Z1000M (115 V)yes
OCZ Z1000M (230 V)yes
Rosewill Lightning-1000 (115 V)yes
Rosewill Lightning-1000 (230 V)yes
Sparkle GW-EPS1250DA (115 V)yes
Sparkle GW-EPS1250DA (230 V)yes
9. Efficiency, Temperature, And Standby Power Consumption

Efficiency in accordance with the 80 PLUS specification

Standby Power Consumption and Temperature Measurement

10. Power Profile Efficiency Overview

11. Conclusion And Comparison Table

We had high expectations of these three tested PSUs. The lofty power ratings and 80 PLUS Gold certifications promised some genuine highlights and the devices did not disappoint when it came to high power output, which is what these devices were designed for in the first place. Unfortunately we did not receive a lot of information on the individual peak power for each 12 V rail from the PSU vendors, hence we have to stick to the plain summary that you’ll get a combined 1000 W across four to six individual 12 V rails.

However, our tests mostly highlighted some weaknesses that should not exist at the highest end. None of the three PSUs actually managed to fully live up to the 80 PLUS Gold standards. The OCZ PSU slipped up a bit in the ripple/noise measurement, Sparkle's build quality undermined its solution a bit, and the Rosewill PSU suffered from impacted energy efficiency at low loads. The bottom line is a bit disappointing, given the high price points in excess of $200, with the OCZ Z1000M scoring best.

Comparison Table

ManufacturerOCZRosewillSparkle
Model Name and NumberZ1000MLightning-1000GW-EPS1250DA
Recommended End User Price$205 USD
$220 USD$300 USD
Power Certification80 PLUS Gold80 PLUS Gold80 PLUS Gold
Weight2.5 Kg6.6 lbs.
5 lbs.
Operating Temperature0 - 50°C??? °C0 - 50°C
Warranty5 years3 years5 years
Power Specifications
SpecificationATX12V v2.2ATX12V v2.3ATX12V/EPS12V
Specified Output Power1000 W1000 W1250 W
Max. Peak Output1100 W1000 WNot Specified
AC Input100 - 240 V100 - 240 V100 - 240 V
AC Voltage SelectionAuto voltageAuto voltageAuto voltage
DC Output +3.3V25 A25 A30 A
DC Output +5V25 A25 A30 A
DC Output +12V (#1)83 A83 A20 A
DC Output +12V (#2)n/an/a20 A
DC Output +12V (#3)n/an/a20 A
DC Output +12V (#4)n/an/a20 A
DC Output +12V (#5)n/an/a20 A
DC Output +12V (#6)n/an/a20 A
DC Output -12V0.8 A0.5 A0.6 A
DC Power +12V Combined1000 W996 W1250 W
PFCactiveactiveactive
Specified Hold-Up Time18 ms> 16 ms≥ 17 ms
MTBF100 000 hours100 000 hours≥ 60 000 Hours 
Cooling Specifications
Main Fan135 mm140 mm140 mm
Main Fan Speed1800 rpm??? rpm2200 rpm
Secondary Fann/an/an/a
Secondary Fan Speedn/an/an/a
Connectors & Environmental
20+4 pin Motherboardx1 (55 cm)x1 (55 cm)x1 (55 cm)
CPU 8-pin/4+4-pin1/x1 (55 cm)1/x1 (55 cm)x1 (55 cm)
PCI Express 6-pin/6+2-pin (Graphics)0/x6 (55 cm)0/x6 (55 - 65 cm)x4 (55 cm)
Molex 4-pin (Peripherals)x6 (55 - 90 cm)x10 (55 - 95 cm)x9 (55 - 85 cm)
SATA Powerx12 (55 - 85 cm)x10 (55 - 95 cm)x12 (55 - 85 cm)
4-pin Floppyx2 (100 cm)x2 (105 cm)x3 (105 cm)
Product Specifics
AccessoriesScrewsScrews, Lacing CordsScrews, Velcro Strips
Cable ManagementYesYesYes
Other Details
Illuminated Fan in Red or Blue; Screw-in Cable ConnectorsC20 Power Connector