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You can use two power supplies in one PC only when the exact motherboard or system documentation specifies how to connect and synchronize them. Check the manual for your board revision before buying an adapter or wiring anything. For example, Gigabyte documents an included dual 24-pin ATX adapter for the TRX50 AERO D, while ASUS documents a dual-PSU arrangement for the Pro WS WRX90E-SAGE SE. Those instructions apply to those specific boards, not automatically to other ATX systems.
First identify what you mean by connecting two PSUs
“Tie two PSUs together” can mean either making a secondary supply turn on and off with the computer, or connecting two supplies to a motherboard designed for that arrangement. These are different configurations. The ATX 24-pin connector carries power and control signals, including PS_ON# and PWR_OK, so starting two supplies together requires a documented control method—not just a way to deliver power.
Before planning the installation, identify the exact motherboard model and revision, the PSU models, and which components each supply would power. Then check the motherboard manual for an explicit dual-PSU procedure, header, or included adapter.
Check whether your motherboard supports two PSUs
Use the instructions for your exact board; do not treat a method documented for one motherboard as a general ATX standard.
#1 Best Overall
- Delivers 500 Watt Continuous output at plus 40 degree. Compliance with Intel ATX 12 Volt 2.31 and EPS 12V 2.92 standards
- 80 PLUS Certified, 80 percentage efficiency under typical load
- Supports (2) PCI E 6plus2pin Connectors. Active (PFC) Power Factor Correction, MTBF: 100,000 hours
- Industry Grade Protections: (OPP) Over Power Protection, (OVP) Over Voltage Protection, (SCP) Short Circuit Protection
- High Quality Components
- Gigabyte TRX50 AERO D: Gigabyte’s manual describes using the included dual 24-pin ATX adapter. It connects to the motherboard, and its two other ends connect to the main and secondary supplies. Gigabyte TRX50 AERO D manual.
- ASUS Pro WS WRX90E-SAGE SE: ASUS’s manual documents a specific dual-PSU cable arrangement for this board. Follow that manual’s diagram and instructions rather than adapting the Gigabyte arrangement. ASUS Pro WS WRX90E-SAGE SE manual.
If your board’s manual does not document a two-PSU setup, use one appropriately rated PSU or ask the motherboard manufacturer for guidance before proceeding. The cited manuals do not establish that a generic adapter or synchronizer is suitable for arbitrary systems.
Install only the documented arrangement
- Read the manuals first. Confirm the exact motherboard model and revision, the specified connection method, and any limits or component connections described by the board and PSU manufacturers.
- Disconnect AC power. Switch off and unplug the supplies before installation, following the PSU manufacturer’s installation instructions. Seasonic’s PSU installation guidance.
- Use the specified adapter or cable arrangement. If the motherboard manual calls for a particular included adapter, use that arrangement; do not substitute an unverified splitter or synchronizer.
- Use cables intended for each PSU. Use the original cables supplied with each unit or cables explicitly confirmed compatible by its manufacturer. Modular PSU-side pinouts are not standardized across all models, so a cable that fits may still be wired differently. Seasonic cable compatibility guidance.
- Stay within connector and cable ratings. Do not exceed rated current. Overload can discolor or melt connectors and cause damage or malfunction. Corsair’s PSU cable guidance.
- Recheck the connections before restoring power. Verify the connections against the board’s diagram and the PSU instructions. If the documented procedure or cable compatibility is unclear, stop and contact the manufacturer rather than modifying wiring.
Why generic wiring advice is not enough
A paperclip test or a wire modification may cause a PSU to start, but that alone does not establish that two supplies will start and stop correctly with a particular motherboard or that the overall configuration is supported. Forum discussion of devices such as Add2PSU is not manufacturer validation for every system. Do not bridge pins, cut cables, or combine PSU outputs based on generic instructions.
Rank #2
- Fully Modular PSU: Reliable and efficient, low-noise power supply with fully modular cabling, so you only have to connect the cables your system build needs.
- Intel ATX 3.1 Certified: Compliant with the ATX 3.1 power standard, supporting PCIe 5.1 platform withstands 2x transient power excursions from the GPU.
- Keeps Quiet: A 120mm rifle bearing fan with a specially calculated fan curve keeps fan noise down, even when operating at full load.
- 105°C-Rated Capacitors: Delivers steady, reliable power and dependable electrical performance.
- Modern Standby Compatible: Extremely fast wake-from-sleep times and better low-load efficiency.
A PSU tester can help check a suspect individual supply, but it does not synchronize two supplies. Use one for diagnosis only, not as a dual-PSU control method. Corsair PSU tester information.
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Before adding a second supply, compare the system’s power requirements with the board’s documented support and the practical installation constraints. The available manufacturer guidance does not provide a general cost or efficiency comparison for one versus two PSUs.
Quick Recap
Best Value
- 80 PLUS GOLD CERTIFIED
- 10-year limited warranty, guaranteeing long term reliable operation
- Fully modular design
- ATX 3.1 & PCIE 5.1
Rank #4
- Delivers 600W Continuous output at plus 40℃. Compliance with Intel ATX 12V 2. 31 and EPS 12V 2. 92 standards
- 80 PLUS Certified – 80% efficiency under typical load. Power good signal is 100-500 millisecond
- Supports (2) PCI-E 6 plus 2pin Connectors. Active (PFC) Power Factor Correction, MTBF: 100, 000 hours
- Industry Grade Protections: (OPP) Over Power Protection, (OVP) Over Voltage Protection, (SCP) Short Circuit Protection
- Hold up time is 16 millisecond minimum within 60 percent load. Input frequency range 50 - 60 in Hz
Rank #3
- 80 PLUS GOLD CERTIFIED
- 10-year limited warranty, guaranteeing long term reliable operation
- Fully modular design
- ATX 3.1 & PCIE 5.1
- Board support: Is a dual-PSU arrangement explicitly documented for the exact board and revision?
- Total load: Can a single suitably rated supply meet the system’s needs, or is a second supply actually necessary?
- Synchronization: Does the board provide a documented way to coordinate startup and shutdown?
- Cable compatibility: Are the necessary cables supplied or explicitly approved for each PSU?
- Physical fit: Can the case safely accommodate both supplies and their cabling?
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