Flip over nearly any desktop computer, open up the side panel, or peek onto a laptop‘s motherboard, and you‘ll see a nest of wires and connectors that look bewilderingly complex. These are the veins and arteries that pump power from the computer‘s power supply unit (PSU) out to all the components that need electricity – the brains, the memory, the graphics, the storage. Without this vital power delivery infrastructure, even the mightiest computer is just a lifeless hunk of silicon and metal.
In this guide, we‘ll demystify these crucial pin connectors, examine why they exist and how they‘ve changed over decades, and take a magnifying glass to the most common types you‘ll see inside a PC case. Grab your safety goggles and lab coat – let‘s get electro-geeky!
The Origins of ATX
Our story begins in 1995 with the introduction of the ATX (Advanced Technology Extended) standard by Intel. This new specification upgraded and replaced the previous AT standard for desktop computer motherboards first introduced by IBM back in 1984.
While AT motherboards relied primarily on two simple power connectors – a large 4-pin Molex and 4-pin Berg – the increasingly complex and power hungry components of the 90s demanded more robust power delivery. Thus arrived ATX and it‘s defining 20-pin connector, capable of delivering vastly more power across additional voltage rails to feed the new components and expansion slots.
Here for the first time was a standard specifically designed to provide ample, reliable electricity within the tight confines of a desktop case. The ATX 20-pin main power connector, along with the new 4 and 6-pin aux connectors allowed unprecedented power levels, the core foundation for nearly three decades of cutting edge PC components to come.
Evolving Power: ATX12V and the 24-Pin Beast
Flash forward to 2003, and the dawn of new high-performance components like the Intel Pentium 4 processor exposed a critical weakness in the maturing ATX specification – it just wasn‘t providing enough juice. Thus was born ATX12V 1.0 and it‘s defining new feature – the 4-pin auxiliary 12 volt CPU power connector.
Delivering as the name implies, a dedicated 12V line for power-hungry new CPU architectures, ATX12V set the stage for an expansion in the capabilities of ATX over successive revisions. By the release of ATX12V 2.0 in early 2003, the standard had grown to incorporate:
- A new 24-pin main connector supporting more 12V power delivery
- Dedicated 6/8-pin 12V connectors for graphics cards
- Specifications for emerging Serial ATA storage connectors
- Significantly increased power output and efficiency requirements
While ATX anchored power delivery innovation for over a decade, its heir ATX12V became the new bedrock. Today‘s desktops and high-end components could simply not exist without the strong foundation laid in evolving standards like ATX and ATX12V.
Technical Power Specifications By Connector
Below we dive into the nitty-gritty power delivery specs for the major ATX connector types seen in modern desktop PCs:
Connector | Max Power | Voltage | Pins | Features |
---|---|---|---|---|
24-Pin ATX | 300W | 3.3V(6pins) 5V(3pins) 12V(12pins) |
24 | 20-pin backwards compatible PS_ON/PWR_OK control Always-on 5VSB |
8-Pin EPS12V | 288W | 12V(8pins) | 8 | Up to 36A per 12V rail |
6+2-Pin PCIe | 300W | 12V(6+2pins | 8 | 75W per 6-pin 150W per 8-pin |
15-Pin SATA | 54W | 12V(2pins) 5V(1pin) 3.3V(1pin) |
15 | Designed for storage drives |
Molex 4-Pin | 66W | 12V(1pin) 5V(2pins) |
4 | Legacy HDD power |
You can see above the extensive power capabilities of connectors like the 24-pin ATX and 8-pin EPS, capable of delivering hundreds of watts across 12 volt rails directly into critical motherboard components and processors.
The PCIe graphics card power adapters also stand out, able to sustain a staggering 300 watts per cable, essential for power hungry modern GPUs.
A Closer Look: Common ATX Connector Types
With the backstory covered, let‘s get hands-on and dive deeper into specifics of the most commonly seen pin connectors hiding in your PC.
The 20-Pin and 24-Pin ATX Power Connectors
The signature connector of the original ATX specification, the iconic 20-pin delivers power from the PSU across multiple voltage rails to the crucial components soldered to the motherboard itself. Designed to provide a steadfast 75W of power minimum, many 20-pin connectors could deliver 100W or more.
The original ATX 20-pin connector
With the introduction of ATX12V 2.0 in 2003, the ATX main connector gained an additional 4-pins tacked onto the end. Bringing the grand total to 24-pins, it represented a huge 50% increase in possible power delivery. Some 24-pin connectors can drive an astounding 200 to 300 watts into hungry motherboard components.
Both connector designs feature multiple voltage rails – most importantly the 3.3V, 5V and 12V lines:
- 3.3V & 5V — Generally lower power I/O, chipsets, memory, and legacy slots
- 12V —- CPU, GPU slots, SATA devices, fans
Additionally, the connectors have important control pin functions:
- PS_ON — Turns PSU on when shorted to ground
- PWR_OK — Indicates PSU passed internal diagnostics
- 5VSB —- Always-on 5V standby power rail
While ATX originally relied heavily on lower 3.3V and 5V for power delivery, recent standards lean towards using 12V exclusively across all components, making the 24-pin king in a modern PC.
EPS12V 8-Pin and 4+4 CPU Power Connector
As CPU power demands climbed in the early 2000s, even the revamped 24-pin ATX connector struggled to keep up. Cue the birth of ATX12V and along with it, the EPS12V CPU connector. Delivering hefty amperage across multiple 12V pins straight from the PSU, it gave hungry CPUs all the clean power they could guzzle.
The EPS connector comes in two common configurations – the 8-pin and "4+4" pin designs:
EPS 8-pin connector
The simple 8-pin variant packs two 12V lines with a theoretical 288W max (36A x 12V), while the 4+4 pin doubles that to four 12V lines and 576W! The idea behind the "4+4" approach is backwards and forwards compatibility – the connector can function as a 4-pin in older boards, but plug in the extra 4-pins when more power is needed.
Designed solely to feed power straight to the CPU voltage regulation circuitry, you‘ll spot these nearly ubiquitous EPS connectors snaking out the top corner of most motherboards. Without them even top-end CPUs could end up underfed!
PCI Express Auxiliary Power Connectors
Modern graphics cards are power hungry beasts, often demanding electricity on par with an entire old-school desktop PC from just 15 years ago! While the PCI Express slot itself can provide 75W of power, that‘s just a drop in the bucket for many gaming GPUs.
The solution comes via the 6/8-pin PCIe power connectors, either plugged directly into high-end graphics cards or adapted to GPU power plugs via modular cables on the PSU:
6+2 pin and 6-pin PCIe connectors
These provide a huge dose of 12V power – 75W per 6-pin plug and 150W per 8-pin. Cards like the beefy new AMD Radeon RX 7900 XTX can require up to 3 plugs for a eye-watering 525 watts!
Additionally, you may spot 6+2 pin connectors which can function either combined as an 8-pin or split apart into a 6-pin in order to maximize compatibility.
Without PCIe power adapters, graphics cards would be strangled down to a tiny fraction of their true power. Gamers everywhere owe their silky smooth frame rates to these little life savers!
Vendor and Industry Analysis
Behind all these evolving power standards are competitors vying to have their connector designs adopted by PSU and motherboard manufacturers. Below we highlight some key vendors and trends shaping the pin connector landscape.
Molex
The ubiquitous Molex 4-pin peripheral connector derives its name from manufacturer Molex, who have supplied micro-fit power adapters to the PC industry since the 1980s. Despite rising competition, Molex still commands 65% market share of global power connector sales including PCIe and SATA adapters used in countless PSUs and components.
TE Connectivity
Molex‘s biggest competitor is TE Connectivity, who manufactures a variety of ATX pin connector types. With the acquisition of industry stalwart company AMP, TE has positioned itself as a rising challenger in next-gen power technologies.
FCI
Known for their Berg Pins connectors used widely on server-grade hardware, FCI is now focusing R&D on smaller and more powerful board-to-board interconnects to meet exploding data center power demands.
Towards Modularity and Ease of Use
Across vendors, we see trends towards tool-less installation, modular all-12V power distribution, and reducing complexity for PC builders and upgraders. ATX as an open standard has strongly encouraged innovation among vendors to meet ever-higher performance demands in computing hardware. These fierce competitors spur each other to excel driving progress in power delivery tech.
Future Power Standards
As computer enthusiasts well know, progress never stands still. With insanely powerful hardware like 300W GPUs and 250W CPUs now reality, existing power delivery standards are being pressed to their limits on the highest end systems.
In just the last 2 years major CPU and GPU makers like Intel, AMD and Nvidia have either introduced or laid the groundwork for long overdue new PSU standards and connectors better suited to coming generations of power hungry computing:
-
ATX 3.0 & ATX12VO – Ambitious new specs from Intel aiming at motherboards and components running on isolated 12V rails only for greater efficiency and power density. Backwards compatible with ATX12V too.
-
PCIe Gen 5 12VHPWR connector – An entirely new 12-pin connector design capable of an incredible 600W for bleeding edge GPUs!
-
12V Internal Bus Architecture – PSU focused standard from Nvidia to complement the above efforts by building desktop PSUs optimized exclusively for highly efficient and simple 12V power distribution, eliminating all other legacy voltage rails.
While adoption of these emerging standards will take several years, the future looks incredibly bright for continued power delivery innovation. Perhaps before long desktop computers will finally wireless too and make all these connectors obsolete – but we aren‘t holding our breath!
Conclusion
Who knew seemingly mundane computer cables and connectors could have such a rich history filled with decades of ingenious innovation? The unique power demands of cutting edge PC components required PSU technology to adapt quickly, birthing ever more robust power delivery conduits to nurture hungry new CPUs and GPUs.
Yet backwards compatibility with legacy hardware means vestiges of even 30 year old standards like ATX and Molex live on in modern systems too – a testament to the creativity and forethought electrical engineers put into these oft overlooked foundations of computing technology.
So next time you crack open a desktop tower or peek behind a laptop‘s ventilated plastic paneling, take a moment to admire the ecosystem of pin connectors that feed and nourish all those delicate electronics within. Without their silent vigil, even the most advanced PC would be little more than a paperweight!