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The standards for power supply units are upgraded in response to technological advancements and changes in the environment.
Older versions can often be used without any issues, but if the latest features are needed, it is important to pay attention to the version.
By knowing what features and improvements were made in each version, it becomes easier to consider the parts configuration for a custom-built PC.
This article explains the versions of power supply unit standards and the specifications of major power supply standards by version.
- Power supply units have different versions of standards
- Functions and performance improve with each version
- Unless the version is very old, there is usually no need to worry
- To use the latest features, use the latest version
This article also explains the basics of power supply unit standards and cables, as well as how to choose one from the perspective of performance and compatibility.
≫ Related article: How to Choose a Power Supply Unit for a Custom PC [Performance / Features / Compatibility]
Select PC parts and online stores to instantly generate an estimate, check compatibility, and calculate power requirements. You can save up to five different builds, making it easy to try out multiple configurations.
≫ Tool：PC Parts Estimation & Compatibility Check Tool
Table of Contents
About Power Supply Unit Standard Versions
The standards for power supply units are upgraded to match the environment.
If the version is not too old, there is no need to worry, but if the latest features are needed, it is important to pay attention to the version.
Power Supply Unit Standards Are Upgraded to Match the Environment
Power supply unit standards are upgraded whenever new features appear in the custom PC world.
For example, as modern GPUs have become more powerful and require more electricity, the 12VHPWR connector was introduced from version 3.0 of the ATX standard.
Therefore, if the 12VHPWR connector is needed, an ATX power supply unit of version 3.0 or later is required.
Besides checking the version, it is also okay to check whether the power supply unit has a 12VHPWR connector.
In addition to connectors, power supply unit standards are regularly upgraded to improve energy efficiency, safety, and compatibility with new devices as technology advances and the environment changes.
No Need to Worry Unless the Version Is Very Old
When choosing a power supply unit for a custom PC, as long as the types and number of connectors and the power capacity match, there is no problem.
Therefore, even without knowing the details of each version and its specifications, it is possible to choose a power supply unit.
However, it is better to avoid very old power supply units.
As mentioned earlier, besides connectors, versions are upgraded for energy efficiency, safety, and compatibility, and newer models generally have better performance.
Also, since performance is usually matched to the lowest component, there is a risk that the full performance of other new parts cannot be utilized.
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Therefore, instead of choosing a very old version (a product released a long time ago), it is safer to choose a relatively new power supply unit released within the last 1 or 2 years.
If the Latest Features Are Needed, Pay Attention to the Version
Basically, there is no need to worry much about the version, but if the latest features are needed, pay attention to the version.
As in the example of the 12VHPWR connector, new connectors may be added according to the environment.
If a connector is added, it can be identified by its specifications or appearance, but for features that cannot be identified by appearance, it is necessary to check the version to see if the desired feature is included.
In custom PCs, various technologies and features appear and disappear, or continue to be used, but sometimes the hardware requirements for using those technologies or features are strict.
If the wrong power supply unit or other parts are selected, those technologies or features may not be usable, so caution is needed.
Specifications by Power Supply Unit Standard Version
This section explains the specifications by version for the current mainstream standards (ATX and EPS).
Note: SFX and SFX-L standards are omitted because the specifications for each version could not be found.
ATX Standard
A power supply unit with the ATX standard is a computer power supply unit designed based on the ATX (Advanced Technology eXtended) standard.
This standard, proposed by Intel in 1995, is a standard for unifying the shape and size of PC cases and motherboards, as well as the arrangement of power connectors.
Ken
Now, let’s look at the features and specifications by version.
| Version | Release Date | Features |
|---|---|---|
| – | Late 1995 | ・4-pin “Molex connector” ・4-pin Berg floppy drive connector ・20-pin Molex Mini-fit Jr. ATX motherboard connector ・6-pin AUX connector |
| ATX12V 1.0 | February 2000 | ・Increased power to 12V rail ・Additional 4-pin 12V connector to supply power to CPU ・Minimum efficiency is 68% at full load |
| ATX12V 1.1 | August 2000 | ・Slight increase in power to 3.3V rail |
| ATX12V 1.2 | January 2002 | ・-5V rail is not required (optional) |
| ATX12V 1.3 | April 2003 | ・Slight increase in power to 12V rail ・Minimum efficiency at full load raised from 68% to 70% ・Introduction of Serial ATA power connector (defined as optional) ・Removed guidance for -5V rail |
| ATX12V 2.0 | February 2003 | ・Most power is supplied by 12V rail ・Two 12V rails required ・ATX motherboard connector expanded to 24 pins ・Introduction of Serial ATA power cable is mandatory ・Minimum efficiency is 60% at light load, 70% at typical load, and 68% to 70% at full load |
| ATX12V 2.01 | June 2004 | ・Removed reference to -5V rail |
| ATX12V 2.1 | March 2005 | ・Slight increase in power to all rails ・Minimum efficiency is 65% at light load, 72% at typical load, 75% at full load ・Recommended efficiency is 75% at light load, 80% at typical load, 77% at full load |
| ATX12V 2.2 | March 2005 | ・Specified high-current series wire terminals for 24-pin ATX motherboard and 4-pin +12V power connectors |
| ATX12V 2.3 | March 2007 | ・Recommended efficiency raised to 80% ・Minimum load requirement for 12V reduced |
| ATX12V 2.31 | February 2008 | ・Added maximum ripple/noise specification ・Clarified DC power hold-up requirements |
| ATX12V 2.32 | May 2020 | ・Late revision of v2.31 specification |
| ATX12V 2.4 | August 2021 | ・Specified in ‘Design Guide for Desktop Platform Form Factors’ version 1.31 |
| ATX12V 2.51 | September 2021 | ・Introduced support for Alternative Low Power Mode (ALPM) *ALPM reduces power consumption when idle or under low load |
| ATX12V 2.52 | October 2021 | ・Requires ALPM support to withstand power cycles every 180 seconds |
| ATX12V 2.53 | December 2021 | ・Added further recommendations for efficiency |
| ATX 3.0 | February 2022 | ・Introduced 16-pin 12VHPWR connector ・Supplies up to 600W (H+), up to 675W (H++) ・Added data line for GPU to negotiate power supply unit capacity ・Spike handling requirements (twice the rated output for 100 microseconds) *This is to handle cases where the latest GPUs temporarily require very high power. |
| ATX 3.1 | 2022 | ・Replaced 12VHPWR power connector with 12V-2×6 power connector |
EPS Standard
The EPS standard is a type of ATX standard, specialized for power supply units for servers and workstations.
This standard is suitable for business computers that require high reliability and stable output, so general users rarely choose it.
EPS power supply units tend to be deeper than typical ATX power supply units, which allows for higher power capacity and more PCI Express connectors.
Now, let’s look at the features and specifications by version.
| Version | Release Date | Features |
|---|---|---|
| 2.1 | 2004 | ・Published design guide |
| 2.8 | 2007 | ・Removed references to common and split 12V planes ・Added high output levels up to 800W ・Reduced hold-up time requirement to 75% of maximum load ・Added cross-load plot ・Added option for stricter 12V regulation ・Added new SSI efficiency requirements (recommended levels and load conditions) ・Increased current for 12V rail ・Reduced maximum Tpwok_on time to 500 milliseconds ・Changed 5VSB to 3.0A for high output levels ・Added reference to PSMI specification ・Changed SMBus section (FRU and PSMI) to 3.3V and made it tolerant to 5V ・Changed 240VA section, removed common plane, changed all 12V outputs to <20A ・Updated acoustic power and airflow requirements ・Added SATA and PCI-Express GFX connectors ・Updated efficiency test methods |
| 2.9 | 2010 | ・Increased 5V current to 30A ・Increased total power for 3.3V/5V to 160W for 650-800W output levels ・Increased 12V1/2 current for 550W-600W output levels ・Relaxed regulation limits ・Added optional regulation limits |
| 2.91 | 2012 | ・Fixed errors in 3.3V and 5V loads at high output levels ・Increased total load for 3.3V/5V to 170W |
| 2.92 | 2013 | ・Added high output levels (850W, 900W, 950W) ・Supported dual GFX and 16xDIMMs ・Increased 5VSB capability to 4A and 6A options ・Added 12V5 and related connectors ・Added new efficiency specifications ・Updated cross-load requirements ・Reduced minimum load for 12V |
Summary: Be Careful If You Want to Use the Latest Features!
The standards for power supply units continue to be upgraded in response to technological advancements and the demand for new devices.
In particular, the power supply unit is an important part that supports the stability and performance of a PC.
Here is a summary of the key points.
- Power supply units have different versions of standards
- Functions and performance improve with each version
- Unless the version is very old, there is usually no need to worry
- To use the latest features, use the latest version
Older versions of power supply units can usually be used without problems, but if the latest features are to be fully utilized, it is important to pay attention to the version.
This article also explains the basics of power supply unit standards and cables, as well as how to choose one from the perspective of performance and compatibility.
≫ Related article: How to Choose a Power Supply Unit for a Custom PC [Performance / Features / Compatibility]
Select PC parts and online stores to instantly generate an estimate, check compatibility, and calculate power requirements. You can save up to five different builds, making it easy to try out multiple configurations.
≫ Tool：PC Parts Estimation & Compatibility Check Tool
