Seasonic S12III 650W


Quality of material


Easy to install


Energy efficiency


Noise level


Value for money



  • The operation does not demand lowering of voltages
  • Quick and easy to install
  • Fan control optimizes the fan speed for quiet operation
  • High cooling efficiency
  • Saving in energy costs


  • There was some feedback that it may shut off your gaming computer

Are you on the lookout for Seasonic S12III 450W power supply? Founded more than decades back, Seasonic is a reliable name in the market. Its key motive is to supply power to the whole system. This entails processors, motherboard, hard drives, and graphics card. Seasonic presents a long list of various power supplies, all with different features, ideal use cases, and at different prices. Although power supply may not be the thrilling component, essentially it is the most crucial one. Once you hook the PC power supply to a wall socket, it distributes power to the remainder of your computer. For the same, it needs different power cables and connectors. From dozens of power supplies in the market, the following Seasonic S12III 450W power supply review lets you make an informed buying decision.

Seasonic S12III 450W Power Supply

Seasonic S12III 450W Power Supply

Possessing 80+ Bronze certification, the Seasonic S12III 450W power supply offers high power conversion efficiency.  It supports ATX12V & EPS12V direct cable wire output. This wattage is the most common for PC systems and therefore, this Seasonic S12III power supply can work with various computers.

The fixed cabling offers all the essential cables needed for a standard PC. Unlike the typical power supply, the fan is placed at the bottom of the unit. This kind of fan positioning offers efficient cooling and dissipates heat from the unit even under highly demanding conditions. The black finish presents an appealing look. For those video cards that require extra power, the power plugs are included.

Key Features

  • With the 80 PLUS Bronze standard, efficiencies are higher than 82%, 85%, and 82% at 20 %, 50 %, and 100 % operating loads, respectively.
  • The mentioned efficiency in combination with the Active Power Factor Correction allows the power supply to reduce energy wastage. So, it converts into savings on energy expenses.
  • Other features include Smart and Silent Fan Control (S2FC) and Double Forward Converter circuit design.
  • The built-in 120 mm sleeve bearing fan is controlled through the Seasonic S2FC fan control.

Final Thoughts

Seasonic has been a prominent name on the power supply market for several years. The above Seasonic S12III 450W power supply review highlights that the Seasonic S12III 450W power supplies are economical and also guarantees outstanding performance. They operate consistently to provide constant power to your PC system. What’s more, them are equipped with an efficient fan system for cooling.

Top 8 Seasonic S12III 450W Power Supply Reviews

1. Seasonic S12III 450W PSUs are great.

Recently retired from owning a computer repair shop for several decades. Have been messing with electronics and computers for over four decades now. Anyway, I’ve been a fan of these SeaSonic PSU’s for years. And I’m still buying them for my own projects in retirement. I have worked on more PSU’s than I care to remember. And I have tried a lot of different PSU’s in my and my customers’ builds over the years. For a long while I preferred PSU’s from PC Power & Cooling, but in the past decade or so Sea Sonic has pulled ahead. They are my top pick now. SeaSonic sells good heavy PSU’s with good components. They’ve been around since 1975 and it shows in their PSU’s. I have some 18 year old PC Power & Cooling PSU’s that have had near-constant use year after year and they just keep going. I keep moving them into new projects and just adding adapters/connectors if needed. They’re great for legacy builds or Linux builds.

Anyway, I expect to get the same longevity out of my SeaSonic PSU’s. Also in my top 5 are Corsairs, CoolerMasters, and on occasion SilverStones (when there’s a sale or I can’t get what I want in a SeaSonic or PC Power & Cooling for a decent price). Not all PSU’s from a company are the same. Especially if they outsource manufacturing here and there. Do your research on specific models that fit your intended project. Always buy more power than you need. And always keep all computers on a UPS (uninterrupted power supply). You’ll be able to keep your PSU’s going a lot longer if you do that. And just so you know, all the companies I stick with are also capable of producing stinkers. I just think they do so less often. All-in-all though, top end SeaSonics have never let me down. My brother likes them too and he’s been working in computers longer than me and is ten times the computer guy than I’ll ever be.

2. High quality build and a perfect fit.

My old AT power supply in my HP tower finally failed after more than ten years and this Seasonic S12III 450W is a very well-built replacement with more connectors, braiding over the cables, and overall, a higher quality build. The thermostatically controlled fan is a bonus.

3. Great PSU (Seasonic S12III 450W)

I got this Seasonic S12III 450W PSU for my current build of Ryzen 5 3600 w/ RX 5700 XT. It does the job great and I like that it doesn’t have ketchup and mustard cables. Yes, the Seasonic S12III 450W is not modular, but cable management was not an issue in my case anyway. Get this if you’re looking for a PSU that’s 60 bucks or less.

4. Reliable and easy to install

While non-modular, the unused cables were fairly easy zip-tied and tucked away. This replaced the power supply in a home office PC after it experienced power delivery issues, giving it a fresh breath of life.

5. Most trusted PC PSU brand for cheap.

I’ve had this Seasonic S12III 450W PSU installed in my PC for over week now and haven’t had a single issue at all. It was easy to install. Being non-modular you have to be at least competent in cable management but that’s a price I am willing to pay for getting the most trusted brand in PC PSU’s at such a cheap price. I am completely satisfied with this PSU so far. Time will tell though but I am optimistic so far.

Update 10/29/21 : I’ve had it for six months and it’s still going strong without issue. I have it installed in a PC that I use as a home media server as well as my daily driver so the PC it is in stays on 24/7, 7 days a week. With that being said this PSU has been put through it’s paces.

Update 05/09/22 : It’s been slightly over a year and still no issues whatsoever. The PC I have it in is still serving the same role so it has definitely been a workhorse. Despite it’s lower quality than expected from Seasonic I would still recommend this Seasonic S12III 450W PSU as a no frills general purpose budget PC PSU.

6. Works fine day 1, will update over time…

Arrived today (jan 02/2021), beautiful cables, looks good, easy to install, really nice fit on the motherboard. my old psu died and i’m trying this one based on reviews and brand. Day 1 working perfectly, really quiet. will update.

Update jan 26/2021, working perfectly ’til now.

Rig: Ryzen 3600, RX480 xfx, gigabyte b550, 7 led fans, abkoncore t505 rgb cooler, ssd + hdd, xpg ram 16gb.

7. Easy Install, Quiet Performer.

So far so good. I will type a full review in a year from now. The only negative, is that it’s not a modular or half modular PSU, but it was easy to install in my PC with the right cables. To top it off, it runs very nicely!

8. Good replacement for a failing supply

This is a well made solid part. Installed it and, while it isn’t completely silent, I immediately noticed how quiet compared to my old supply it was. It has all the connectors you’d expect with a good length for a largish tower case.

Enjoyed this Seasonic S12III 450W review? Then be sure to check out our other guides of the Best 1200W Power Supply and the Best 650W Power Supply.