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Seasonic M12D 750w ATX PSU

Simulated Load Testing

Published: 21st March 2009 | Source: Seasonic | Price: £145.88 | Author: James Napier

Simulated Load Testing

To provide our readers with the most accurate results, Overclock3D uses a professional grade SunMoon SM-268+ ATE load tester capable of placing a sustained load of 1690w across a total of six rails (including +5vsb and -12v) on the PSU. Unlike our previous resistor-based load tester, the SM-268+ gives us the ability to adjust amperage loads in increments as small as 0.01A while also measuring voltages and wattage readings on-screen.

During today's tests, we will be placing the M12D under 25%, 50%, 75% and 100% load levels at both room temperature and inside a hot box regulated to a temperature of around 50°C. Additional cross load tests will also be performed under these conditions to simulate how the PSU would perform with a heavily uneven distribution of load.

Seasonic M12D 750w SM-268+ Results @ Room Temp
	+3.3v	+5.0v	+12v1	+12v2	+5vSB	-12v	AC Watts /  DC Watts	Efficiency	Intake /  Exhaust	Δ Temp
Test 1 (Low)	5.50A	3.75A	6.25A	6.25A	0.75A	0.20A	226w /  199w	88.05%	22.6°C /  25.2°C	2.6°C
	3.35v	4.96v	12.45v	12.43v	4.99v	-12.40v
Test 2 (Med)	11.00A	7.50A	12.20A	12.20A	1.5A	0.40A	431w /  388w	90.00%	23.1°C /  29.4°C	6.3°C
	3.30v	4.91v	12.37v	12.35v	4.94v	-12.41v
Test 3 (High)	16.50A	11.25A	18.75A	18.75A	2.25A	0.60A	662w /  588w	88.82%	23.9°C /  31.5°C	7.6°C
	3.24v	4.86v	12.27v	12.26v	4.89v	-12.47v
Test 4 (Full)	22.00A	15.00A	25.00A	25.00A	3.00A	0.80A	885w /  782w	88.36%	24.5°C /  32.8°C	8.3°C
	3.19v	4.80v	12.18v	12.20 v	4.84v	-12.55v
Test 5 (x-load)	23.00A	20.00A	0.50A	0.50A	0.75A	0.20A	233w / 191w	81.97%	20.2°C / 26.5°C	6.3°C
	3.27v	4.87v	12.45v	12.44v	4.96v	-12.45v
Test 6 (x-load)	3.00A	5.00A	31.00A	31.00A	0.75A	0.20A	906w / 801w	88.41%	23.5°C /  31.6°C	8.1°C
	3.25v	4.87 v	12.18v	12.19v	4.92v	-12.84v

*slobbers*...do you see what I see? Yes the 90% efficiency at a DC load of 388w is not a typo and come in at just the kind of load level the average enthusiasts PC system is likely to run at when under a light stress. The rest of the results also back up the M12D's 80-PLUS Silver certification with an average of 88% efficiency being recorded throughout all of the non-crossload testing.

Unfortunately it's not all good news though as the M12D puts out some slightly shady voltages in Test 1 with the +12v rails bordering on 12.45v. Test 2 and 3 manage to bring these voltages down a tad with the additional load being placed on the PSU, but throughout the testing I couldn't help but notice all the voltage outputs bouncing around like a 5yr old who's just downed a can of Red Bull. Seriously, it was quite hard to take a reading without it flicking over to another number +/-0.03v either side of what I'd begun writing down.

Seasonic M12D 750w SM-268+ Results @ 50°C
	+3.3v	+5.0v	+12v1	+12v2	+5vSB	-12v	AC Watts /  DC Watts	Efficiency	Intake /  Exhaust	Δ Temp
Test 1 (Low)	5.50A	3.75A	6.25A	6.25A	0.75A	0.20A	226w /  199w	88.05%	50.5°C / 54.5°C	4.0°C
	3.35v	4.96v	12.45v	12.43v	4.99v	-12.40v
Test 2 (Med)	11.00A	7.50A	12.20A	12.20A	1.5A	0.40A	431w /  388w	90.00%	52.0°C / 54.2°C	2.2°C
	3.29v	4.91v	12.36v	12.33v	4.94v	-12.41v
Test 3 (High)	16.50A	11.25A	18.75A	18.75A	2.25A	0.60A	660w /  588w	89.09%	50.9°C / 56.5°C	5.6°C
	3.24v	4.85v	12.27v	12.26v	4.88v	-12.48v
Test 4 (Full)	22.00A	15.00A	25.00A	25.00A	3.00A	0.80A	885w /  782w	88.36%	51.8°C / 59.7°C	7.9°C
	3.19v	4.79v	12.18v	12.29 v	4.82v	-12.56v
Test 5 (x-load)	23.00A	20.00A	0.50A	0.50A	0.75A	0.20A	233w / 190w	80.85%	50.6°C / 55.5°C	4.9°C
	3.26v	4.87v	12.45v	12.44v	4.96v	-12.45v
Test 6 (x-load)	3.00A	5.00A	31.00A	31.00A	0.75A	0.20A	906w / 801w	88.41%	50.0°C / 58.6°C	8.6°C
	3.25v	4.87 v	12.17v	12.16v	4.92v	-12.84v

Things didn't get any better for the voltage stability in the 50°C testing either (why would they?) with most of the voltage readings being around -0.01v lower than the room temperature tests, and still fluctuating. One thing that did have me grimacing slightly was the -12v rail in Test 6 which hit -12.84v. Sure it's nowhere near as likely to do damage as the +12v rails, but some better regulation wouldn't have gone amiss.

Efficiency managed to stay almost exactly the same with that magical 90% still being achieved in Test 2 despite the PSU components being under a lot more stress due to the increased temperature.

Seasonic M12D 750w Scope Results @ 50c
	+3.3v	+5.0v	+12v1	+12v2
Test 1 (Low)
Test 2 (Med)
Test 3 (High)
Test 4 (Full)
Test 5 (x-load)
Test 6 (x-load)

Both the +3.3v and +5.0v rails managed to put out some nice clean lines on the scope, with ripple staying below 8mV in most cases and only hitting as high as 11mV in test 4 and 5. The +12v1 and +12v2 rails on the other hand were giving me crazy eyes with the scope set to 2ms, producing some weird patters that I've never come across before.

Slowing things down to 5ms readings gave a clearer picture of what was going on with ripple staying below 43mV throughout the testing. Not bad at all, even though I have had better elsewhere darling.

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