Sparkle Power SPI220LE 80 Plus FlexATX PSU

TESTING

For a fuller understanding of ATX power supplies, please read the reference article Power Supply Fundamentals & Recommended Units. Those who seek source materials can find Intel's various PSU design guides at Form Factors.

For a complete rundown of testing equipment and procedures, please refer to SPCR's PSU Test Platform V.4. The testing system is a close simulation of a moderate airflow mid-tower PC optimized for low noise.

In the test rig, the ambient temperature of the PSU varies proportionately with its output load, which is exactly the way it is in a real PC environment. But there is the added benefit of a high power load tester which allows incremental load testing all the way to full power for any non-industrial PC power supply. Both fan noise and voltage are measured at various standard loads. It is, in general, a very demanding test, as the operating ambient temperature of the PSU often reaches >40°C at full power. This is impossible to achieve with an open test bench setup.

The 120mm fan responsible for "case airflow" is deliberately run at a steady low level (~6-7V) when the system is run at "low" loads. When the test loads become greater, the 120mm fan is turned up to a higher speed, but one that doesn't affect the noise level of the overall system. Anyone who is running a system that draws 400W or more would definitely want more than 20CFM of airflow through their case, and at this point, the noise level of the exhaust fan is typically not the greatest concern.

Great effort has been made to devise as realistic an operating environment for the PSU as possible, but the thermal and noise results obtained here still cannot be considered absolute. There are too many variables in PCs and too many possible combinations of components for any single test environment to provide infallible results. And there is always the bugaboo of sample variance. These results are akin to a resume, a few detailed photographs, and some short sound bites of someone you've never met. You'll probably get a pretty good overall representation, but it is not quite the same as an extended meeting in person.

SPCR's high fidelity sound recording system was used to create MP3 sound files of this PSU. As with the setup for recording fans, the position of the mic was 3" from the exhaust vent at a 45° angle, outside the airflow turbulence area. The photo below shows the setup (a different PSU is being recorded). All other noise sources in the room were turned off while making the sound recordings.

INTERPRETING TEMPERATURE DATA

It important to keep in mind that fan speed varies with temperature, not output load. A power supply generates more heat as output increases, but is not the only the only factor that affects fan speed. Ambient temperature and case airflow have almost as much effect. Our test rig represents a challenging thermal situation for a power supply: A large portion of the heat generated inside the case must be exhausted through the power supply, which causes a corresponding increase in fan speed.

When examining thermal data, the most important indicator of cooling efficiency is the difference between intake and exhaust. Because the heat generated in the PSU loader by the output of the PSU is always the same for a given power level, the intake temperature should be roughly the same between different tests. The only external variable is the ambient room temperature. The temperature of the exhaust air from the PSU is affected by several factors:

• Intake temperature (determined by ambient temperature and power output level)
• Efficiency of the PSU (how much heat it generates while producing the required output)
• The effectiveness of the PSU's cooling system, which is comprised of:
  • Overall mechanical and airflow design
  • Size, shape and overall surface area of heatsinks
  • Fan(s) and fan speed control circuit

The thermal rise in the power supply is really the only indicator we have about all of the above. This is why the intake temperature is important: It represents the ambient temperature around the power supply itself. Subtracting the intake temperature from the exhaust temperature gives a reasonable gauge of the effectiveness of the power supply's cooling system. This is the only temperature number that is comparable between different reviews, as it is unaffected by the ambient temperature.

NOTE: Because of the SPI220LE's tiny size, it was difficult to position in our PSU thermal load tester. We used various pieces of foam to block off spaces not covered by the PSU.

TEST RESULTS

Ambient conditions during testing were 21°C and 19 dBA. AC input was 120V, 60Hz.

ANALYSIS

1. EFFICIENCY

Above ~60W, efficiency exceeded 82% all the way to full output, which is excellent. At the low end, 80% efficiency was maintained to about 40W output, which means the unit definitely meets the 80 Plus requirement of 80% at 20% of rated power (44W). The low power efficiency numbers speak for themselves; they are excellent, matching the Seasonic 300SFD 80 Plus at the ~40W mark, and staying well above 70% even down at 20W load. Unfortunately, the Seasonic was not tested at loads lower than 40W.

We began testing PSUs at 20W output recently; compared to the 73% efficiency of the Sparkle, the two other tested PSUs measured far lower, 61% for the 450W Corsair VX and 65% for the Seasonic S12II-380. However, it's important to note that at 20W load, even a big 10% efficiency difference accounts for only 2W.

The efficiency at 20W was not quite the equal of the picoPSU, which we measured at 79.5% or 77%, depending on whether the 90W or 120W power brick was used. At 40W load, too, the SPI's efficiency was a couple points behind the picoPSU.

2. VOLTAGE REGULATION was excellent. There was virtually no sag on any of the lines, especially the all-important 12V lines, even up to the rated output.

3. RIPPLE

The 12V ripple at full load was a little higher than what we normally measure, but still way below the 120mv allowed by ATX12V. Ripple at the other voltages remained well below the allowable 50mv.

4. POWER FACTOR was close to perfect across all loads, as is the norm for most power supplies with active correction circuitry.

5. LOW LOAD PERFORMANCE

The PSU started consistently without any load with a very small power draw of 2.2W. There was a low level electronic squeal with no load which disappeared once a +5VSB load was enabled. Power draw was a very low 0.5W when the unit was switched off.

7. TEMPERATURE & COOLING

Cooling was not bad, given the very impeded airflow path of the densely packed unit. Beyond about 100W load, the temperature rise through the PSU exceeded 20°C, which resulted in fairly high exhaust air temperature in our cool lab. Users would do well to try to keep the intake air temperature below 30°C in order to ensure that the PSU's internal components don't get too hot.

8. FAN, FAN CONTROLLER and NOISE

Initially, the fan did not turn on during the 20W or 30W load tests. It came on during the 40W test when the exhaust air temperature reached 42°C. The exhaust temp dropped after the fan turned on, and we recorded 40°C in the final data.  

The fan sounds much worse than the dBA numbers suggest, mainly because it has such a pure tone.  It could be heard clearly even when its SPL at one meter was more or less at ambient. The fan sounded whiny and it seemed to have multiple pure tones, somewhat reminiscent of an old hard drive with worn ball bearings.

The fan controller is very sensitive, with quick changes up or down in fan speed whenever there is a sudden changes in load (similar to that of a software being opened or a CPU intensive task being started).  It has too little hysteresis to be unobtrusive.

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