The Seasonic PRIME Titanium PSU (650W, 750W, 850W) Review: Mythical Performance
by E. Fylladitakis on April 7, 2017 9:00 AM ESTHot Test Results
The electrical performance of the new Seasonic PRIME Titanium units is unbelievable. We are unsure how Seasonic even managed such power quality and performance figures.
| Seasonic SSR-650TD - Main Output | ||||||||
| Load (Watts) | 130.29 W | 325.85 W | 488.11 W | 650.38 W | ||||
| Load (Percent) | 20.04% | 50.13% | 75.09% | 100.06% | ||||
| Amperes | Volts | Amperes | Volts | Amperes | Volts | Amperes | Volts | |
| 3.3 V | 1.78 | 3.34 | 4.45 | 3.34 | 6.67 | 3.33 | 8.89 | 3.33 |
| 5 V | 1.78 | 5.03 | 4.45 | 5.03 | 6.67 | 5.01 | 8.89 | 5.01 |
| 12 V | 9.6 | 12.02 | 24.01 | 12.02 | 36.01 | 12.01 | 48.02 | 12 |
| Line | Regulation (20% to 100% load) |
Voltage Ripple (mV) | |||||
| 20% Load | 50% Load | 75% Load | 100% Load | CL1 12V |
CL2 3.3V + 5V |
||
| 3.3V | 0.2% | 4 | 4 | 6 | 8 | 4 | 6 |
| 5V | 0.25% | 4 | 6 | 6 | 8 | 4 | 6 |
| 12V | 0.15% | 4 | 4 | 6 | 8 | 6 | 6 |
| Seasonic SSR-750TD - Main Output | ||||||||
| Load (Watts) | 150.34 W | 375.71 W | 562.75 W | 750.4 W | ||||
| Load (Percent) | 20.05% | 50.09% | 75.03% | 100.05% | ||||
| Amperes | Volts | Amperes | Volts | Amperes | Volts | Amperes | Volts | |
| 3.3 V | 1.81 | 3.33 | 4.53 | 3.33 | 6.8 | 3.33 | 9.07 | 3.33 |
| 5 V | 1.81 | 5.02 | 4.53 | 5.02 | 6.8 | 5.01 | 9.07 | 5.01 |
| 12 V | 11.25 | 12.02 | 28.11 | 12.02 | 42.17 | 12 | 56.23 | 12 |
| Line | Regulation (20% to 100% load) |
Voltage Ripple (mV) | |||||
| 20% Load | 50% Load | 75% Load | 100% Load | CL1 12V |
CL2 3.3V + 5V |
||
| 3.3V | 0.2% | 4 | 4 | 6 | 8 | 4 | 6 |
| 5V | 0.25% | 4 | 6 | 6 | 10 | 4 | 6 |
| 12V | 0.18% | 4 | 4 | 6 | 8 | 6 | 8 |
| Seasonic SSR-850TD - Main Output | ||||||||
| Load (Watts) | 170.49 W | 426.27 W | 638.38 W | 851.07 W | ||||
| Load (Percent) | 20.06% | 50.15% | 75.1% | 100.13% | ||||
| Amperes | Volts | Amperes | Volts | Amperes | Volts | Amperes | Volts | |
| 3.3 V | 1.84 | 3.34 | 4.6 | 3.34 | 6.91 | 3.33 | 9.21 | 3.33 |
| 5 V | 1.84 | 5.04 | 4.6 | 5.04 | 6.91 | 5.02 | 9.21 | 5.02 |
| 12 V | 12.89 | 12.03 | 32.23 | 12.03 | 48.35 | 12.01 | 64.46 | 12.01 |
| Line | Regulation (20% to 100% load) |
Voltage Ripple (mV) | |||||
| 20% Load | 50% Load | 75% Load | 100% Load | CL1 12V |
CL2 3.3V + 5V |
||
| 3.3V | 0.2% | 4 | 4 | 6 | 8 | 4 | 8 |
| 5V | 0.25% | 4 | 6 | 8 | 10 | 6 | 8 |
| 12V | 0.15% | 4 | 4 | 8 | 10 | 8 | 6 |
We had to check our readings down to the fourth decimal point, as the voltage regulation on the main 12V line is below 0.15%, meaning that a cheap 2-decimal point voltmeter might not even display a difference at all across the entire load range. The 3.3V/5V lines are a little less tightly regulated but still remain amongst the most stable that we have ever seen, with our worst result being 0.24% for the 5V line of the 850W model.
The power quality of all three PRIME Titanium units is insanely good, with our oscilloscope never reading a voltage ripple above 10mV under any operating conditions. We have never seen such effective filtering before on consumer level products.
Despite the exceptional efficiency of the PSUs, the fans are significantly more lively with the units operating into our hotbox, as the thermal control circuit is trying to maintain low internal operating temperatures. The PRIME Titanium units all begin with noise figures when lightly loaded but their fans will keep increasing their speed alongside with the load, reaching clearly audible figures with loads above 300 Watts and even becoming noisy with >46 dB(A) figures when they units are very heavily loaded. The maximum temperature that our instruments recorded was just below 80 °C, which is very low for an 850W PSU operating at maximum capacity, meaning that Seasonic could trade some of the thermal performance for better acoustics. These units do come with a 12-year warranty though, so the designer could perhaps not afford >90°C figures appearing into any of these units.
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emn13 - Saturday, April 8, 2017 - link
Higher rated PSUs necessarily have reduced low-load efficiency, even PSU's as good as these. So it's highly unlikely the 600W fanless is a 1000W model minus the fan; that would significantly reduce the efficiency at low loads, which, given their aim with these models, I seriously doubt is a tradeoff seasonic would have been willing to make.SkipPerk - Wednesday, May 3, 2017 - link
Seasonic makes a 500W fanless unit, but it is simply a 1350W unit without the fan and some big heat sinks. Enermax also makes robust fanless units up to 500W, but they are basically the same high-wattage unit with the fan removed and larger heat sinks. You might as well buy a 1200W or 1350W PSU that does not spin up until it hits a certain wattage (usually 300W to 400W).Lolimaster - Friday, April 7, 2017 - link
Considering they're titanium, most people just use 1 gpu and don't OC their cpu. They should launch more models, like 450-550w with fan.blahsaysblah - Saturday, April 8, 2017 - link
Not that i wouldnt have minded getting one, but read the wiki on 80 Plus. Gold is plenty fine. Im very happy with my SFX Corsair SF450 PS that has never turned on its fan(GPU is GTX 1060 6GB). Never seemed hot to touch. A good GOLD PS seems to not generate enough waste as heat to matter. Its almost one year since using it in new PC.Of course its positioned nicely, big vent up, for convection, per fine print, and its right under a vent, SilverStone SG13B case. One 140mm fan upfront is only system fan. Its does not get noisy level RPMs either. (just get silverstone atx to sfx adapter that is vented, centers PS, dont get corsair one. last i checked a year ago...)
blahsaysblah - Saturday, April 8, 2017 - link
dang, no edit. i want to add, i made my own set of power cables(all) to de-clutter build. so my experience may be slightly different than yours.djscrew - Friday, April 7, 2017 - link
Oh wow, the reviews are in and our product is exceptional. Now let's see if we can improve these margins! How would we go about that? Let's see... maybe we can find a manufacturer who can do it for less.surt - Sunday, April 9, 2017 - link
Online reviews are absolutely merciless when manufacturers do this, it has killed the sales of more than one vendor over the years. Remember OCZ?Solidstate89 - Friday, April 7, 2017 - link
Interesting. Has Seasonic moved away from Sanyo Denki fans? I thought they used them exclusively?FriendlyUser - Friday, April 7, 2017 - link
Great review as always. Having a good PSU is essential for the longevity of the components. I mean, what's the point of the 16-phase VRM design of your MB if you are feeding it crap power? And how far can you overclock your GPU if your 12V line is full of ripple and noise? The efficiency is the cherry on top.Being a very satisfied owner of a Seasonic Platinum 850W, the only reason I'm not buying the Prime is because the Platinum is already extremely good and it's powering my home server 24/7 for years now.
Lolimaster - Friday, April 7, 2017 - link
You should probably change for the 10-20% efficiency, which your server will run at most of the time.That's why lower than 600w Titanium PSU's are more important than useless 750-850w where low load efficiency is not as good.
Looking at the numbers you're getting 90% efficiency at near 35w load on the 650w vs 90% efficiency at 55w on the 850w model.