DC Load Regulation and AC Ripple
Establishing an accurate load is critical to testing and evaluating a PC power supply. PCPerspective’s power supply test bench can place a precise DC load on the PSU under test. Each power supply is tested under controlled, demanding conditions up to its maximum rated load (at 40ºC). Our current suite of tests includes:
• DC Load Regulation
• AC Ripple and Noise
• Differential Temperature
The EVGA 750 Supernova G3 power supply was evaluated on both features and performance. A full range of equipment was used to test the power supply under controlled load conditions.
• (2) CSI3710A Programmable DC load (+3.3V and +5V outputs)
• (4) CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• (2) 200W Precision resistor load bank (+12V5 and +12V6)
• Switchable precision resistor load bank (-12V and +5VSB)
• Agilent 34401A digital multimeter (Accuracy ±0.0035% vDC)
• Extech 380803 Power Analyzer (Accuracy ±0.5% of full scale)
• DS1M12 "StingRay" digital oscilloscope (20M S/s with 12 Bit ADC)
• Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)
The following connectors were used to attach the EVGA 750 G3 PSU to the PCPerspective power supply test equipment.
• (1) 20+4 pin ATX
• (2) 8-pin EPS/ATX12V
• (6) 6-pin PCI-E
• (2) SATA
• (3) Molex
DC Output Load Regulation
To simulate demanding and maximum loading conditions, the EVGA 750W G3 power supply was connected to the load testers and supplied with 120 VAC. In this test we are interested in seeing how well a PSU can maintain the various output voltages while operating under different loads.
The ATX12V V2.2 tolerance for voltages states how much each output (rail) is allowed to fluctuate and has tighter tolerances now for the +12V outputs. I have also included a second table of expanded tolerances (±1% to ±6%) for reference.
The following tables list the DC voltage results for the 750 Supernova G3 PSU while operating on 120 VAC, 60 Hz.
The 750W Supernova G3 PSU produced outstanding voltage regulation on all of the DC outputs. The three main outputs stayed within ±1% of the recommended guidelines; only dropping 0.01V for the +3.3V and +5V outputs and 0.16V for the +12V output as the combined load increased from 75W to 750W.
AC Ripple and Noise on the DC Outputs
The amount of AC ripple and noise present on the DC outputs was checked using a digital oscilloscope. This AC component may be present in the KHz range where most switching power supplies operate or it may be more prevalent at the 60 Hz line frequency. We adjust the O-scope time base to look for AC ripple at both low and high frequencies. The ATX12V V2.2 specification for DC output noise/ripple is defined in the ATX12V Power Supply Design Guide.
Ideally we would like to see no AC ripple (repetitive) or noise (random) on the DC outputs – the cleaner the better! But in reality there will always be some present. I measured the amplitude of the AC signal (in millivolts, peak-to-peak) to see how well the power supply complied with the ATX standard. The following table lists the ripple/noise results during all of the load tests for the main output voltages of interest.
The Supernova 750W G3 power supply also did an excellent job of keeping the AC ripple and noise well under control. Note that even the +12V output peaked at only 12 mV p-p; while delivering a 58A load.
Who is the actual
Who is the actual manufacturer? Do EVGA produce it themselves or they are partnering with Seasonic or CWT etc ?
“Here are a few pictures
“Here are a few pictures showing the layout and components inside the EVGA Supernova 750W G3 power supply. The Supernova G3 Series is built by Super-Flower and is based on a second generation Leadex platform.”
Have the powersupply
Have the powersupply manufacturers ever standardized the modular connectors? I have a bunch laying around that I am too chicken to try.
Hi, I asked in the office
Hi, I asked in the office chat and unfortunately the answer is no. The modular connectors are not standardized between manufacturers or even between PSUs from the same manufactures (sometimes you can swap them within the same line but not always).
Question: how well does this compare to the Seasonic Focus Plus series (SSR-750FX) in your opinion? The F+ kindasorta won by a slim margin in JohnnyGuru’s testing, but their rating system is a little… eccentric.
Obviously they’re both awesome units but if you had to choose…
I’ve been a SS loyalist and pricing on the F+ series is very competitive, but there was some concern with the F+ units’ small fan resulting in annoying noise.
Another question: what’s the benefit of a fully modular PSU? Do they expect people to run their PSUs without the ATX12v cable? Is it just for easy-ish replacement if you happen to damage a cable? Would be a lot more valuable IMHO if they bundled shorter and longer cables for different case/mobo combos.
Thanks, its always good to
Thanks, its always good to know that readers find our reviews helpful.
First question: Yes, both the EVGA 750W G3 and the Seasonic 650W Focus+ Gold PSUs proved to be excellent. Performance wise they are very close, both with very good voltage regulation, AC ripple suppression and efficiency (the 750W G3 had slightly better AC ripple suppression). The EVGA G3 also uses a slightly larger fan (128mm vs the Seasonic F+ 120mm) but they both are relatively quiet through mid-power range and both have FDB. And they are both backed by a 10-year warranty. So your final purchasing decision may come down to price – which one has the lower cost when you want to buy one (at this moment the Seasonic 750W F+ is about $20 less than the EVGA 750W G3).
Second question: I personally prefer a semi-modular PSU with a fixed 24-pin, 4+4 ATX CPU, and a pair of PCI-E cable/connectors. Its not like these are optional. Being fully modular adds more connection points (potential for added resistance/slight voltage drop) and a little bulk to the front of the PSU. I suspect manufacturers are going fully modular to lower production costs by eliminating the extra labor required to hand solder fixed leads.