There are old PC guides that tell you which plug goes where, and then there is PlayTool, which tells you why the plug exists, how many amps it can carry and what happens when somebody gets clever with an adapter.
Read PlayTool’s PC power connector guide
The page was last updated July 15, 2008 and remains an unusually dense reference to PC power-supply cabling. It covers the original PC motherboard power cables, the four-pin peripheral connector, floppy power, the old six-pin auxiliary connector, SATA power, 20-pin and 24-pin ATX, ATX12V, EPS12V and the six- and eight-pin PCI Express family.
Each section goes well beyond a photograph.
There are pinouts, wire colors, voltage rails, connector part numbers, maximum current figures and practical wattage estimates. A summary table tracks how the connector set changed from the original 1981 PC through ATX in 1995, ATX12V and EPS12V, and PCI Express-era systems.
The page also captures the engineering reason those standards changed. More current through a conductor means more voltage drop and more heat. Adding wires and contacts spreads the load. That is why newer connectors often appear to be older connectors with extra pins bolted on: electrically, that is sometimes almost exactly what happened.
“Black to black” or smoke
The original PC motherboard power arrangement used two adjacent connectors. PlayTool preserves the old technician’s rule for installing them: place the black ground wires together.
Get that wrong and the site’s description becomes beautifully concise: smoke and sparks.
The article is equally skeptical of adapters. A 20-to-24-pin ATX adapter does not magically create additional current-carrying capacity; it merely adds more wire and another set of contacts to the path. The author points out that overloaded connectors can heat up and melt, and that a system which appears stable may become a problem later when a high-draw PCI Express card is installed.
There is also a particularly valuable warning about certain late-1990s Dell systems whose motherboard power connectors looked like standard ATX but were wired differently. Plugging a normal ATX supply into one of those proprietary arrangements could produce exactly the kind of electrical archaeology nobody wants to perform after the smoke clears.
This is why detailed hobbyist technical pages age so well. Product listings disappear. Forum images rot. Manufacturer documentation moves. But a hand-built page with the terms ATX12V 2.0, Molex 39-01-2200, EPS12V, PCI Express 6-pin, SATA power and PS_ON# remains searchable decades later.
That kind of specificity is a major reason CacheRat’s Ancient Web research list is useful as more than a nostalgia catalog.
Old hardware does not care that the Web redesigned itself.
It still wants the right voltage on the right pin.