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Seasonic Focus FM 650W Gold PSU Review: A Fantastic Semi-Modular PSU

Author: HP   Date:


Seasonic Focus FM 650W Gold Review

Seasonic is a company that needs no introduction and they are known for making amazing power supplies with excellent performance. Seasonic's Focus PSUs are split into two separate series, the Focus FM and the Focus Plus series. The Focus FM is Seasonic's semi-modular PSUs rated at only 80 Plus Gold and comes with 7 years of warranty while the Focus Plus is fully modular and is available in both 80 Plus Gold and Platinum efficiencies and comes with 10 years of warranty. We recently reviewed the Seasonic Focus Plus SSR-750FX Gold PSU which seriously impressed us with its amazing internal build quality and exceptional performance. Another good thing about Seasonic's Focus power supplies is that they come in a small 140mm footprint which can help in cases where space is premium.

Pricing & Warranty

Seasonic's Focus FM series offers four power supplies ranging in capacities of 450W, 550W, 650W and 750W. Today we will be reviewing the Focus FM SSR-650FM model that retails for $80 on Amazon/Newegg and comes with 7 years of warranty. This is a semi-modular PSU and is 80 Plus Gold certified which means it guarantees greater than 87%, 90% and 87% efficiency at 20%, 50% and 100% operating loads, respectively. At $80, the SSR-650FM is about $5 cheaper compared to other semi-modular 650W Gold PSUs from other manufactures but the other manufactures do not come anywhere close to Seasonic's 7-year warranty coverage.


Since the Focus FM line comes in a semi-modular design, that means only the essential cables come pre-attached which generally means the 24Pin ATX, a single PCIe and the 8Pin CPU cables. The Focus Plus line on the other hand comes with no pre-attached cables because it uses a fully modular design but that also makes them more expensive than the Focus FM line. Build quality remains the same between the Focus Plus and Focus FM line so if you want to save some money and don't care about having a fully modular PSU, then the Focus FM series might be what you need.

Seasonic Focus FM 650W Gold PSU Review

Seasonic has equipped their Focus series with a 120mm Fluid Dynamic Bearing (FDB) fan which is extremely reliable and generates considerably less operating noise and heat than ball bearing fans. Since we are talking about the fan, I want to mention a difference between the Focus Plus and Focus FM series regarding fan operation. The Focus Plus line comes with a fan control button at the back of the power supply that allows the PSU to turn off the fan for silent operation during idle or low powered activities if the loading condition is below 30%. This button allows you to switch between the Seasonic S2FC (fan control without Fanless Mode) and the S3FC (fan control including Fanless Mode) but the Focus FM series lack this fan control button so the fan will always be spinning (S2FC mode only).

Seasonic's Focus PSUs include ±3% tight voltage regulation which significantly helps with the stability of your machine when it's running. When your computer is running, the current power draw can suddenly change for your CPU or GPU load and when this happens, the less change in voltage, the better thus resulting in better stability for your computer. Cheap power supplies don't do this very well, and can often damage the components of your computer so be very careful when purchasing some random power supply that you find on websites such as Amazon and Newegg.

Seasonic Focus FM 650W Gold Power Supply Review

Most of the really good PSUs out there are rated for 50°C operating temperature but the majority of them are generally rated for 40°C. This is a pretty difficult standard to meet and Seasonic has achieved that with the Focus series and the SSR-650FM comes with a 50°C operating temperature. Seasonic has also implemented a cable-free connection design solution where instead of cables, the back panel and the PCB are connected by a copper plate. This lowers the chance of production errors during manual insertion and also improves power efficiency.


Seasonic SSR-650FM Specifications
Max. DC Output:650W
Over Voltage Protection:Yes
Weight:6.20 lbs
Form Factor:Intel ATX 12 V
Dimensions:140 mm (W) x 150 mm (L) x 86 mm (H)
Fan Size:120 mm
Fan Control:S2FC
Fan Bearing:Fluid Dynamic Bearing
Life Expectancy:50,000 hours at 40 °C, 15 % - 65 % RH
Cable type:Flat black cables (modular)
Webbed cables (attached)
Operating Temperature:0 - 50 °C
MTBF @ 25 °C, excl. fan:100,000 hours
AC Input:Full Range
Protection:OPP, OVP, UVP, OCP, OTP, SCP
Safety and EMC:cTUVus, TUV, CB, CCC, BSMI, EAC
Environmental Compliance:Energy Star, RoHS, WEEE, ErP Lot 6, REACH
Warranty:7 Years
Voltage:100 V - 240 V
Current:9 - 4.5 A
Frequency:50 Hz - 60 Hz
Load Range
Rail+3.3V+5V+12V-12 V+5 VSB
Max.(Amps):20 A20 A54 A0.3 A3 A
Max.(Power):100 W648 W3.6 W15 W
Total Continuous Power:650 W
Main Connector20+4Pin
+12V Rails:Single
PCI-Express Connector:2 x 6+2-Pin
SATA Power Connector:6
Connectors:1 x ATX connector 20+4 pin (610mm)
1 x 4/8 Pin CPU (650mm)
2 x 6+2 pin PCIe (675mm+75mm)
6 x SATA (450mm+120mm+120mm+120mm)
3 x Peripheral (450mm+120mm+120mm)
1 x FDD (110mm)


Seasonic Focus FM 650W packaging box

The SSR-650FM comes in a simple but elegant box that stands out when you first see it due to the bright yellow color. Looking at the front of the box, we see the Seasonic logo on the top left corner followed by the 'Focus Gold' text in the center and '650FM' model number in the top right corner.

On the back, you will see a list of the SSR-650FM's features such as the 80Plus Gold rating, DC to DC converter design, +12V output, tight voltage regulation, reliable aluminum solid capacitors, 120mm FDB fan, compact design, semi-modular cabling, and a 7-year warranty. Size-wise, the SSR-650FM is 140mm wide, 86mm tall and 150mm long and weighs 6.20 lbs.

Seasonic Focus FM 650W box

If you have bought a Seasonic PSU before, you know their packaging is excellent and the SSR-650FM is no exception. The SSR-650FM comes protected by two high density foams as shock absorbent to prevent any accidental damages during shipping. The power supply is enclosed inside a cloth bag that definitely gives it a premium feel to it. Also, Seasonic includes a separate cloth bag for you to store your modular cables. Most manufactures package their power supplies in plastic bags so it's nice to see Seasonic go the extra mile with their packaging.

Seasonic includes a set of Velcro straps, four mounting screws, several zip ties, Focus case badge, an AC power cord, a user's manual and the bundle of modular cables. The manual has all the information you need to know about the power supply such as how to set up your power supply and basic troubleshooting. There's a void sticker on one of the corners of the PSU and tampering with the PSU of course voids the warranty.

Seasonic Focus FM 650W cables

The cables are of ample length and you can look at the table above for connector count and for cable lengths. Unlike the Focus Plus series, the Focus FM comes with cables that do not have capacitors in them which allow for tighter folding and greater flexibility. Having capacitors in the cables is done for ripple filtering but it also makes the cables bulky and difficult to fold and route around the case.

Build Quality

Seasonic Focus FM 650W Gold Internal Quality

Underneath the cover of the PSU, a clean layout interior is seen, where the circuit board is seated directly on the main board rather than being connected with separate cables. The integration and soldering quality is top notch and the SSR-650FM uses all high quality Japanese capacitors throughout the build. Japanese capacitors from Nippon Chemi-con are both used in the primary and secondary side.

Japanese manufacturers such as Nippon Chemi-Con are known for making excellent capacitors and have a reputation for excellent quality control and are also said to use a refined electrolyte with better sealing capacity that are more resilient to higher temperatures. The primary bulk capacitor is provided by Nippon Chemi-Con and is rated at 400v 450uf 105°C.

Seasonic Focus FM 650W Gold outside transistors

Moving on, you will notice that the SSR-650FM is using four heatsinks that help with dissipating the heat from the primary and secondary side which is very good. There's a small PCB where the AC receptacle and power switch are installed which also holds the first part of the EMI suppression filter. So the input filtering begins on this small PCB that has some X and Y capacitors attached to it and then trails onto the main PCB for completion.

Seasonic Focus FM 650W Gold inside

The SSR-650FM is featuring a full bridge LLC topology and LLC resonant converter on the primary side while the secondary side uses synchronous rectification and DC-to-DC converters. The wires are color-coded so it is easy to take everything apart and re-house if needed. All of the filtering is handled by several Nippon Chemi-Con capacitors which is great.

Seasonic Focus FM 650W Gold fan

Looking at the back of the power supply, we can see that the connectivity is fairly standard. The modular panel includes 4 sockets and the panel is nicely labeled to let you know what each socket is used for.

Seasonic Focus FM 650W Gold fan

The SSR-650FM comes with a 120mm Fluid Dynamic Bearing (FDB) fan with a max 2050 RPM and is rated for 0.45A at 12V. The fan is by Hong Hua and the model number is HA1225M12F-Z and it is connected to the PCB using a 2-pin connector. Fluid dynamic bearings fans have much longer lifespans compared to sleeve bearing fans and this makes them great for power supplies.

Test Methodology

Our goal here is to simulate realistic loading conditions to see how well the PSU can maintain the various output voltages while operating under different loads. All of the testing is conducted at an ambient temperature of 22°C. These tests will be performed at several load levels, from low (100W) to high (600W) or higher depending on the PSU. We are looking for results as close to 12V, 5V and 3.3V as possible. We are also measuring the PSU noise levels during our load testing. Sound pressure level readings were measured from about 100cm away from the PSU.

Below is a table listing the tolerances for each power supply voltage rail based on the ATX specification version 2.2. We have also included a table with various dBa ratings to help describe the various noise levels based on real world situations.

Power Supply Voltage Tolerances
RailToleranceMin. VoltageMax. Voltage
+3.3V± 5% (±0.165V)+3.135V+3.465V
+5V± 5% (±0.25V)+4.75V+5.25V
-5V± 10% (±0.50V)-4.50V-5.50V
+12V± 5% (±0.60V)+11.40V+12.60V
-12V± 10% (±1.20V)-10.80V-13.20V

Noise Levels (dBA)
Lawn Mower:90 dBA
Vacuum Cleaner:80 dBA
City Traffic:75 dBA
Conversation:65 dBA
Air Conditioning:60 dBA
Floor Fan:50 dBA
Electric Hum:45 dBA
Refrigerator Hum:40 dBA
Rustling Leaves:30 dBA
Pin Falling:15 dBA
Just Audible:10 dBA
Threshold of Hearing:0 dBA


Seasonic Focus FM 650W Load Tests
DC Load+3.3V+5V+12VEfficiencyFan SpeedPSU Noise
100W3.31V5.01V12.01V89.1%480 RPM<15 dBA
200W3.28V4.99V12.00V89.3%490 RPM<15 dBA
300W3.29V4.98V11.99V89.8%530 RPM17 dBA
400W3.29V5.02V11.97V90.2%660 RPM19 dBA
500W3.29V5.00V12.00V89.8%1120 RPM26 dBA
600W3.29V5.00V11.98V90.2%1330 RPM34 dBA

The SSR-650FM performed excellent in our tests and the voltage regulation was outstanding. The SSR-650FM stayed within ±1% of the ATX guidelines. Unlike the Focus Plus series which use the S3FC technology (Hybrid mode), the Focus FM series utilize the S2FC technology which means the fan will always be spinning. During low loads, the fan stays under 500 RPM so it's pretty silent and even during medium loads is still quiet, but the fan does become audible during high loads. Overall, the noise levels are more than acceptable for low and medium loads which is what this PSU will run at most of the time.


The Seasonic Focus FM SSR-650FM has everything you can ask for in a high quality PSU such as a compact design, high warranty coverage, quiet fan, great packaging and it is certainly affordable at $80. Price-wise, you are looking at a $10 difference between the Focus FM SSR-650FM ($80) and the Focus Plus SSR-650FX ($90). But keep in mind that the Focus Plus series come with a 10-year warranty and are fully modular and also feature the Hybrid fan mode button. If you are happy with the 7-year warranty, semi-modular design and don't care about the hybrid fan mode, then the Focus FM SSR-650FM is definitely one of the best semi-modular PSUs you can buy out there.

The SSR-650FM features a silent 120mm FDB fan which makes it great for quiet home or office use and its compact design makes it great to build highly efficient systems in small footprints. The interior design of the Seasonic SSR-650FM is modern and the integration quality is top-notch. It sports a clean and elegant build quality that has ample power to drive a high end gaming computer with no problem. The trend for small form factor computers has been increasing over the years due to the hardware components becoming more efficient and Seasonic is helping to drive the efficiency movement by releasing the Focus series of power supplies in compact designs.

+ Affordable
+ High Build Quality
+ Quiet FDB Fan
+ Fantastic Packaging
+ 7-Year Warranty
+ High Efficiency
+ Compact Design

- None

I'm currently running the SSR-650FM in one of my builds and I have to say that this is a fantastic power supply. It's whisper quiet during gaming, browsing the web, watching movies and office work so Seasonic has done an excellent job with the SSR-650FM. The compact design, high efficiency and top-notch build quality make the SSR-650FM the best semi-modular PSU you can buy. The 7-year warranty shows how confident Seasonic is in the quality and reliability of their products. Overall, the Seasonic Focus FM SSR-650FM easily deserves our gold award.

Final Score    10

RelaxedTech Gold