DC Load Regulation
PSU Testing Methodology
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
• Efficiency
• Differential Temperature
• Noise
All three of the Seasonic PRIME Titanium Series power supplies were 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 (+12V)
• (3) 218W Precision resistor load bank (+12V)
• 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)
• Powerstat Variable Autotransformer, 1.4 KVA, 0-140 VAC
• Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)
The following cables/connectors were used to connect the Prime Titanium power supplies to the PCPerspective power supply test equipment.
• (1) 20+4 pin ATX
• (2) 8-pin EPS/ATX12V
• (4) 6-pin PCI-E (650W and 750W), (6) 6-pin PCI-E for the 850W
• (6) SATA
• (6) Molex
DC Output Load Regulation
To simulate demanding and maximum loading conditions, the power supply was connected to the load testers and supplied with a constant 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 three PSUs while operating on 120 VAC, 60 Hz.
Seasonic PRIME 650W Titanium PSU
Seasonic PRIME 750W Titanium PSU
Seasonic PRIME 850W Titanium PSU
All three PRIME Titanium power supplies produced outstanding voltage regulation on all of the DC outputs while delivering the full rated load. And the three primary rails stayed within the claimed 0.5% load regulation!
What really impressed us however is how close the numbers are from one power supply to another. This is a very good indicator of high quality.











I know what my next power
I know what my next power supply will be!
Love Seasonic
My only regret is that I may
My only regret is that I may never own one of these, because my present PSU (1kw Seasonic KM3 gold) is taking too long to die.
Has Seasonic got their coil
Has Seasonic got their coil whine situation sorted out yet? I think I’ve had 1 out of 6 Seasonic X and Platinum series units that didn’t have an unacceptable level of noise (what the hell is the point of quiet fans and passive operation if the circuitry is squealing like a pig with its nuts in a vice?), so I’ve been using SuperFlower based PSUs over the last year or so.
The SuperFlower Leadex plugs/sockets are also 100x better than Seasonic’s death grip ones which always feel like they’re taking excessive force to insert in my experience.
Not sure, but I’ve had the
Not sure, but I’ve had the same problems. I learned that it’s better to buy Corsair with Seasonic as the key, because then you can at least do an advanced exchange. It gets old having to wait for a replacement after three times.
Key=oem
Key=oem
I have not experienced any
I have not experienced any high frequency whine from any of the units I have tested – dead silent.
And no catsup-and-mustard
And no catsup-and-mustard coloring at the end of those beautiful cables! Awesome!
I picked up one of the 750W
I picked up one of the 750W models to replace a 5 year old Seasonic X (which was great). Have been extremely satisfied with these PSUs and i recommend them to everyone. Keep up the great reviews guys!
I just built a new machine
I just built a new machine with an X850 Gold. No regrets buying it but the primes look really nice too.
I dont know why they didnt go with a Sanyo Denki fan.
“Weaknesses :
• Close
“Weaknesses :
• Close spacing of connectors on front panel can make disconnecting cables a little difficult for people with large fingers”
Seems like clutching at straws 🙂
Maybe sometimes it OK to say “This product is actually perfect”
But how does it compare to
But how does it compare to other PSUs?
Theyre among the best ATX
Theyre among the best ATX PSUs you can get.
Excellent review as always, I
Excellent review as always, I just bought the PRIME 850 W Titanium.
However you may want to update your review as Seasonic have now raise their industry leading warranty to 12 years (from 10 years).
I found out about it on Toms Hardware.
http://www.tomshardware.com/news/seasonic-prime-12-year-warranty,33791.html
http://seasonic.com/prime/
Keep up the great work.
Should I still buy this in 2022???