Seasonic
Focus GX-750 ATX 3
AUTHOR:Onie T.
TESTED BY:Lucas N.
Published:

The Seasonic FOCUS GX-750 ATX 3 (2024) is a 750W, fully modular ATX 3.1 power supply with a hybrid fan mode. As part of the upgraded FOCUS GX series, it now complies with ATX 3.1 and PCIe 5.1 standards. As of this publication date, Seasonic released this power supply in mid-November 2024 at an MSRP of $129.99 USD for the Black colorway, and $139.99 USD for the White colorway. 

Labs tested two samples of this power supply. During testing the first unit failed in the 115V, 12V OCP tests, reaching 87.1 A before shutting down. However, the second sample performed well, maxing out at approximately 115%. Given this performance, we believe the first unit may have had a defect, and we still recommend the power supply overall.

This version features Seasonic’s new ‘OptiSink’ internal design. The naming scheme may be slightly confusing, as this power supply is part of the FOCUS V4 series and may also be listed with “2024” appended to the product name. The FOCUS GX-750 ATX 3 (2024) is recommended for its good load regulation and abundance of included accessories.

WHAT YOU NEED TO KNOW

THE GOOD

  • Load Regulation

    The power supply performed well across all rails with a slight dip on the 5Vsb rail. However, the 5Vsb still remained within specifications, and critical components will not be reliant on it.

  • Colorways

    This power supply is available in both white and black, making it one of the few white Seasonic power supplies on the market.

THE BAD

  • Nothing at the time of writing

THE REST

  • Overall

    Labs tested two samples of this power supply. Despite the failure of the first unit, the FOCUS GX-750 ATX 3 (2024) performed as expected for its class and price range. It is recommended for its solid load regulation and included accessories.

LINKS
Where to buy*
Newegg

*This website uses affiliate links. Purchases made through these links may provide compensation to Linus Media Group.

Hardware
HardwareNotes

The Seasonic FOCUS GX-750 ATX 3 (2024) is an ATX form factor power supply that comes with a range of accessories, including a PSU and cable bag, a PSU tester, and velcro cable ties. The cables are flexible with an etched pattern. This power supply is available in both black and white colorways. 

The newly released version is designed with Seasonic’s ‘OptiSink’ internal design, which reorganized internal components to improve heat dissipation. A 135 mm fluid dynamic bearing fan ensures efficient cooling. 

The power ratings and specifications align with expectations for this price range. On the Seasonic specifications webpage it specifies that the Operating Temperature is 0°C to 50°C, though we cannot verify this through testing.

In the Box

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Front of the box.

Construction

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Power input side of the PSU.

Case Format
Cable Form
Colour
Colour Theme
Case Width
Case Height
Case Length
Case Effective Length
Mass
Fan & Cooling
Top of the PSU displaying the fan.

Top of the PSU displaying the fan.

Cooling Method
Fan Diameter
Specifications
Bottom of the PSU displaying the specifications.

Bottom of the PSU displaying the specifications.

ATX Version
80PLUS Rating
Cybenetics ETA
Cybenetics Lambda
Input Frequency Range
Input Voltage Range
Operating Temperature Range
Storage Temperature Range
Cables
1xMotherboard
24-pin Motherboard:
2xCPU / PCIe
4+4-pin CPU:
2xCPU / PCIe
6+2-pin PCIe:
1x12VHPWR / 12V-2x6
12V-2x6 (600W):
1xPeripheral / SATA
Molex:
Molex:
Molex:
2xPeripheral / SATA
SATA:
SATA:
SATA:
SATA:
Power Ratings
+12 V+5 V+3.3 V+5 Vsb-12 V
CURRENT62 A20 A20 A3 A0.3 A
WATTAGE744 W100 W15 W3.6 W
750 W

Please note that the above ratings are manufacturer advertised specifications.

Features & Software
Features & SoftwareNotes

The FOCUS GX-750 ATX 3 (2024) includes a single hybrid fan mode, controlled by Seasonic’s “Digital Hybrid Fan Control”. It operated in three stages: Fanless Mode, Silent Mode, and Cooling Mode. 

The power supply also includes standard protections and is backed by a 10-year warranty, typical for power supplies in this class.

Modes
Protections
Over Current Protection (OCP)
Over Power Protection (OPP)
Short Circuit Protection (SCP)
Over Temperature Protection (OTP)
Over Voltage Protection (OVP)
Under Voltage Protection (UVP)
Performance
PerformanceNotes

In performance testing, the FOCUS GX-750 ATX 3 (2024) demonstrated solid load regulation across all output rails. The only minor variance was a slight drop on the 5Vsb rail under heavy load, though still within acceptable specifications. The 12V rail maintained steady performance, showing a minimal voltage drop of only 0.127 V across the entire 750W load range, meeting ATX specifications. 

Ripple testing was less impressive than the load regulation. The ripple noise is on the high end compared to other power supplies we have tested, but all test points are still within specifications. We measured a peak-to-peak ripple of 42 mV on the 12V rail, and 36 mV and 41 mV on the 5V and 3.3V rails, respectively. 

The unit handled most power excursion tests, failing only at some of the fastest durations. The lowest observed voltage was below specifications reaching only 11.12 V. Although this is technically a failure, it is unlikely to impact most users, as it passes other excursions even at high temperatures.

Voltage Ripple
Load Regulation
Power Excursion

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Productivity & Efficiency
Productivity & EfficiencyNotes

The FOCUS GX-750 ATX 3 (2024) is 80PLUS Gold certified, delivering 91% efficiency at 50% of its maximum rated load. It maintained its efficiency across the entire power range, satisfying all 80PLUS requirements. 

In brownout tests, it sustained dropouts for up to 13 ms for both 115V and 230V inputs, with minor destabilization occurring only after 19 ms. The power supply’s protections activated relatively low at 115% for the 12V OCP, and the 5V and 3.3V rails engaged at around 140%. Lower wattage rails triggered at 210% and 300%, though these are less utilized and pose minimal risk. 

Over Power Protection engaged at 123% of the rated load, and the 12V rail alone handled up to 71 A, or 115% of its rating. While this lower protection threshold may result in occasional shutdowns under extreme loads, it serves to safeguard connected components.

Efficiency
Brownout
Brownout/Hold-Up Duration 115 V 60 Hz 20°C
Over Current Protection (OCP)
Test Configuration
Video Overview
Test Bench
AC Source
Automated Test Software
DC Load Mainframe
Dual Channel Loads
Chroma 63610-80-20
Environmental Chamber
Microphone
Multimeter
ON/OFF Controller
Chroma 80613
Power Meter
SC/OVP Tester
Chroma 80612
Thermocouple Scanner
Noise Analyzer
Single Channel Loads
Chroma 63640-80-80

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