Seasonic X-750 750W PSU 10 Year Redux

Author:Paul Johnson

Editor:Kyle Bennett

Date: Thursday , March 28, 2019

One of our readers' favorite PSU topics has been when we look back at a previously reviewed PSU that has been in service for a long while, and whether or not that PSU will still meet ATX spec and handle its previously rated wattage load. Today we have a Seasonic PSU that has been in service for a decade.


When building a "new" PC one of the components that enthusiasts often reuse is their power supply. And, why not? For the most part, the ATX12v/EPS standards over the years have not changed nearly as much as other facets of the market and, barring some issues with efficiency and low power sleep states, most of the changes that have impacted power supplies are not noticeable to the end user so long as they push the on button and their system powers up.

However, as people do often reuse power supplies through multiple builds over multiple years, we have often been asked the question, "What happens to a power supply after you have been using it for an extended period of time and how does it perform relative to when it was new?" In partial answer to that question, we reevaluated the SilverStone Olympia 1000W back in March of 2015 after that unit had been in service for 7 years and the results were interesting. We also reevaluated the CoolerMaster Real Power Pro 100W in March of 2018 after that unit had been in service for 10 years.

Today, we have the opportunity to do another redux....again. That said, even when looking at a third example today, we still do not have a definitive answer for you. Nor do we have a scientifically rigorous answer for you. What we DO have for you is another data point as we take a second look at the Seasonic X-750 (SS-750KM) power supply that we first reviewed in 2009 that has been running in one of our gaming/work PCs (Core 2 Extreme QX9770 3.20Ghz, 4GB Corsair XMS3 DDR3-1333, ASUS GTX260, Seagate ST31500341AS, PIONEER DVR-111D) over the last 10 years. In this second look, we will be rerunning all of the load tests that we ran initially on this unit and then comparing how this particular sample performed ~10 years ago, to how it is performing today, after all those years of use.

One Last Dance With The X-750?

In the power supply realm when consumers think of quiet and efficient power supplies one of the first company that comes to mind is Seasonic and today we have our third crack at a Seasonic branded unit. This review marks the launch of Seasonic’s newest line of power supplies the X series with the unit we have here today being the X-750 (SS-750KM).

Seasonic is one of the older companies producing consumer power supplies having been founded in 1975 and entering the PC power supply production market in 1980. During that more than 40 years as a company Seasonic has cultivated lines of power supplies that are today some of the standard bearers for efficiency and quiet computing. This focus, and its reputation for quality, has lead to an explosion in production as Seasonic can be found providing OEM services on various model lines for Antec, XFX, Corsair, PC Power and Cooling, and of course under its own Seasonic brand.

At the time of the X-750’s release, Seasonic was positioning this product as part of their flagship product line:

Sea Sonic Electronics Co., Ltd. today announces the release of the company’s flagship "X" series power supplies, the world’s first ever 80PLUS Gold certified, full modular, multi-output ATX standard power supplies for general sales.

The "X" series, available in 650 & 750 watts output power, showcases the advancement in power supply design technology and embedded inside each unit are two (2) patented features to make the "X" series the most advanced PC power supply on the market today.

Seasonic patented DC Connector Module with integrated VRM (Voltage Regulation Module) . This patented feature takes the concept of modularity one step further and provides not only complete modular system integration flexibility but at the same time, reduces the current transfer between the PSU main PCB which means enhanced power utilization efficiency, output stability, safety and security.

Hybrid Silent Fan Control2. This patented features upgrades the current Seasonic market leading S2FC (Smart & Silent Fan Control) design with three (3) separate operating modes, fanless, silent and cooling. This unique fan control circuit in combination with the world leading Sanyo Denki San Ace PWM (Pulse Width Modulation) shaped blade, ball bearing fan, makes the "X" series the leader in power supply silence and cooling technology.

In addition, the "X" series power supplies utilizes the highest quality level of material usage such as solid polymer capacitors, high grade and high temperature electrolytic capacitors, dual sided PCB and even scratch resistant power supply case coating, all to make the Seasonic "X" series, the highest standard power supply available in the market today.

The "X" Series is the crowning achievement of Sea Sonic Electronics’ 34 years of dedication to power supply research, design and production and the continued pursuit of ideas and purpose to better the environment and achieve our slogan, Green Innovation Powers Your Life.

When it came time to see if the rubber met the road, we found that, for its time and place, the Seasonic X-750 was indeed a flagship product as it earned a Gold Award with our conclusion being this :

The Bottom Line? The Bottom Line is that users should have but one question about the Seasonic X-750. Do I want ground or accelerated shipping on my order? The X-750 is the real deal and provides users with an efficient, stable, well regulated, amazingly well built, and superbly quiet basis to build any system around. Be it a HTPC or a high-end gaming rig the X-750 can do it all and do it all well. This power supply is quite simply one of the most exciting products that has crossed our test bench (and not exploded) in quite some time. The Seasonic X-750 PSU is close to perfection on almost every front. At a price of $199.99 (MSRP) this unit may seem pricey for 750W but you get what you pay for and then some with the Seasonic X-750.

So, we know the X-750 started off life as an award winning for its time power supply, but the question today is, has this unit’s performance changed over the last ~10 years that this unit has been in service? Let's move on and see.