Circuit board
Eight or more layers of copper and fibreglass. The faint lines are traces - the wiring between every part, some tuned in length to the millimetre so signals arrive together.
- Form factor
- ATX, 305 × 244 mm
- Layers
- Typically 6–10
Diagrams example
Read-only showcaseA PC motherboard, every slot and socket
A technical illustration: every slot, socket and header on an ATX motherboard, explained.
100%
Everything on this diagram
The same content as the picture, as text: every part and what it says when you open it.
Rear I/O panel
The ports that show at the back of the case: USB, networking, audio and the display outputs for the processor's own graphics.
- Typically
- USB-A and USB-C, Ethernet, audio
- Display
- For integrated graphics
VRM heatsinks
Cover the voltage regulators that turn the supply's 12 volts into the roughly one volt the processor runs on, at well over a hundred amps.
- Converts
- 12 V to about 1 V
- Why heatsinks
- The conversion makes heat
CPU power, 8-pin
Feeds the processor's regulators directly from the power supply. High-end boards add a second one.
- Pins
- 8 (4 + 4)
- Feeds
- The processor's regulators
CPU socket
Where the processor sits. In a land-grid socket the pins are in the socket, not on the chip, so it is the socket that must never be touched.
- Type
- Land grid array
- Careful
- The pins are in the socket
Memory slots
Four DDR5 slots. With two sticks, use the second and fourth from the processor - the manual's A2 and B2 - so both channels are used.
- Type
- DDR5
- With two sticks
- Slots A2 and B2
- Maximum
- Typically 192 GB
Fan headers
Four-pin connectors for case and processor fans. The board speeds them up and down by temperature.
Pins: 4, speed-controlled
Main power, 24-pin
The main connection from the power supply, feeding everything except the processor's own regulators.
- Pins
- 24
- Feeds
- The board and its slots
M.2 slots
For NVMe solid-state drives, which lie flat on the board under these heat spreaders. The top one connects straight to the processor and is the fastest.
- Drive type
- NVMe SSD, 2280 size
- Fastest
- The top slot, wired to the processor
PCIe x16 slot
The graphics card slot, wired straight to the processor and reinforced with steel, because a modern graphics card is heavy.
- Generation
- PCIe 5.0
- For
- The graphics card
- Reinforced
- Steel-armoured
Other expansion slots
A short x1 slot and a long slot that is wired for fewer lanes than it looks - for network, capture or sound cards.
- Short slot
- PCIe x1
- Long slot
- x16 size, x4 wiring
Chipset
A hub for everything the processor does not connect to directly: most USB ports, the SATA ports and the lower slots.
- Connects
- USB, SATA, lower slots
- Under
- A passive heatsink
SATA ports
For 2.5-inch SSDs and hard drives, angled so the cables run neatly to the back of the case.
- Ports
- 4
- Speed
- 6 Gb/s each
CMOS battery
A coin cell that keeps the clock and the settings when the computer is unplugged. Taking it out for a minute resets the settings.
- Type
- CR2032
- Resets settings
- If removed
Audio codec
The sound chip, under a shield and set apart from the rest of the board by a gap in the copper, to keep electrical noise out of the audio.
Isolated by: A split in the board's ground
Front panel header
Where the case's power button, reset button and lights plug in. The manual's diagram of these nine pins is the most-read page in it.
Connects: Power and reset buttons, lights
More examples like this
Seat maps, org charts, process maps and racks: every shape becomes a region.
