Differences Between ATX 3.0 and ATX 3.1 Standards
As PC hardware performance continues to improve, the power consumption of graphics cards and CPUs is rising, especially when high-end graphics cards are under heavy load. Their peak power consumption often exceeds the nominal TDP value, which can trigger the power supply's overload protection mechanism, causing the system to shut down or restart.
To meet the power demands of the new generation of high-performance hardware and improve the power supply’s ability to handle instantaneous dynamic overloads, Intel introduced the ATX 3.0 power supply standard in March 2022, followed by an update to the ATX 3.1 standard in September 2023.
Comparison Between ATX Standards
ATX 2.4 |
ATX 2.53 |
ATX 3.0 |
ATX 3.1 |
|
| 16Pin Native Interface | No Requirement |
No Requirement |
12VHPWR (> 450W standard) |
12V-2×6 (> 450W standard) |
| Instantaneous Peak Power | No Requirement |
No Requirement |
200% (100μς) |
200% (100μς) |
| Voltage Power-Off Retention Time | 17ms at full load |
17ms at full load |
17ms at full load |
12ms at full load 17ms at 80% load recommended |
| 12V Voltage Deviation | -5% ~ +5% |
-5% ~ +5% |
-7% ~ +5% |
-7% ~ +5% |
| PCIe Voltage Deviation | No Requirement |
No Requirement |
-8% ~ +5% |
-8% ~ +5% |
Extremely Light Load Efficiency (10W or 2%) |
No Requirement |
Requirement ≥60% Recommend ≥70% |
Requirement ≥60% Recommend ≥70% |
Requirement ≥60% Recommend ≥70% |
| ALPM Replaces Low Power Mode | Not Supported |
Support |
Support |
Support |
| T1/T3 Boot Sequence | T1 < 200ms 100ms < T3 < 250ms |
T1 < 150ms 100ms < T3 < 250ms |
T1 < 150ms 100ms < T3 < 250ms |
T1 < 150ms 100ms < T3 < 250ms |
1 The name "12VHPWR" has been changed to "12V-2x6", and the pin length of the socket on the board side, such as the graphics card side, has been adjusted to enhance safety. The wire material remains unchanged.
Enhanced 12V-2x6 Connector
The 12VHPWR connector was updated to the 12V-2x6 connector in ATX 3.1 by the PCI-SIG organization. This new design offers:
- Longer conductor terminals for better conductivity.
- Shorter sense pins, allowing the GPU to power down immediately if the connection is compromised.
This update addresses issues seen with the 12VHPWR connector, which previously caused some issues with melted connectors, particularly on the GPU side.
Note that the 12V-2x6 and 12VHPWR connectors differ only in their socket design, while the modular cables remain identical and fully compatible.
Improved Hold-Up Time
Hold-up time refers to the duration a PSU can maintain stable power output after an interruption or drop in input voltage, measured in milliseconds.
The ATX 3.1 standard has relaxed the requirements for voltage hold-up time, reducing it from 17ms at full load to 12ms at full load, with a recommendation of 17ms at 80% load. However, this does not signify a downgrade of the standard. The actual hold-up time depends on the specifications and test data of individual products, not just the standard