3.5 Given a scenario, install and configure motherboards, central processing units (CPUs), and add-on cards.
📘CompTIA A+ Core 1 (220-1201)
Motherboard connector types are physical connection points on a motherboard. These connectors allow the motherboard to communicate with add-on cards, storage devices, power supplies, and internal components.
For the exam, you must:
- Identify different connector types
- Know what each connector is used for
- Understand where they are found
- Know which devices connect to them
- Recognize modern vs legacy connectors
1. Peripheral Component Interconnect (PCI)
What is PCI?
PCI is an older expansion slot used to connect add-on cards to the motherboard.
Purpose
PCI allows expansion cards to communicate with the CPU and system memory.
Common Devices Connected
- Sound cards
- Network interface cards (NICs)
- Older modem cards
- Older capture cards
Key Characteristics
- Parallel communication (older technology)
- Slower than PCIe
- White-colored slot (commonly)
- Mostly found on very old systems
Exam Notes
- PCI is considered legacy
- Rarely found in modern systems
- Replaced by PCIe
2. PCI Express (PCIe)
What is PCIe?
PCIe is the modern replacement for PCI and is the most common expansion slot used today.
Purpose
Provides high-speed communication between the motherboard and expansion cards.
Common Devices Connected
- Graphics cards (GPU)
- Network cards
- RAID controllers
- Sound cards
- High-speed storage adapters
PCIe Slot Sizes
- PCIe x1 – Small cards (network, USB expansion)
- PCIe x4
- PCIe x8
- PCIe x16 – Graphics cards
Key Characteristics
- Serial communication (faster and more efficient)
- Each lane provides dedicated bandwidth
- Backward compatible (smaller cards fit into larger slots)
Exam Notes
- PCIe x16 is used for graphics cards
- PCIe is not the same as PCI
- PCIe lanes affect performance
3. Power Connectors
Power connectors supply electrical power from the power supply unit (PSU) to the motherboard and components.
3.1 24-Pin ATX Power Connector
Purpose
Supplies main power to the motherboard.
Characteristics
- 24 pins (older systems used 20-pin)
- Mandatory for system operation
3.2 CPU Power Connector (4-Pin / 8-Pin)
Purpose
Provides dedicated power to the CPU
Types
- 4-pin (older)
- 8-pin (modern CPUs)
- Some boards support 4+4 pin
3.3 PCIe Power Connectors
Purpose
Provide additional power to high-performance graphics cards.
Types
- 6-pin
- 8-pin
- 6+2 pin
Exam Notes (Power Connectors)
- Motherboard will not boot without CPU power
- PCIe power connectors are not interchangeable with CPU connectors
- Always match the correct connector type
4. SATA (Serial ATA)
What is SATA?
SATA is a data connector used to connect storage devices.
Purpose
Allows communication between the motherboard and storage devices.
Common Devices Connected
- Hard Disk Drives (HDD)
- Solid State Drives (SSD)
- Optical drives (DVD/Blu-ray)
SATA Versions
- SATA I – 1.5 Gbps
- SATA II – 3 Gbps
- SATA III – 6 Gbps (most common)
Key Characteristics
- Thin, flat cable
- One device per cable
- Hot-swappable (supported by OS)
Exam Notes
- SATA is data only, not power
- Power is supplied separately from the PSU
- SATA III is backward compatible
5. eSATA (External SATA)
What is eSATA?
eSATA is an external version of SATA.
Purpose
Used to connect external storage devices at SATA speeds.
Characteristics
- Higher performance than USB 2.0
- Less common today
- No power delivery (usually)
Exam Notes
- eSATA is external
- Largely replaced by USB 3.x and USB-C
- Still appears on some older systems
6. Headers
What are Headers?
Headers are internal connectors on the motherboard used to connect front-panel and internal components.
Common Types of Headers
6.1 Front Panel Header
Connects:
- Power button
- Reset button
- Power LED
- HDD activity LED
6.2 USB Headers
Connect:
- Front USB ports on the computer case
Types:
- USB 2.0 header
- USB 3.0 / 3.2 header
6.3 Audio Header
Connects:
- Front panel audio ports (headphone and microphone)
6.4 Fan Headers
Connect:
- CPU fan
- Case fans
Types:
- 3-pin (DC control)
- 4-pin (PWM control)
Exam Notes (Headers)
- Headers are inside the case
- Incorrect connection may cause buttons or ports not to work
- CPU fan must be connected for system safety
7. M.2
What is M.2?
M.2 is a high-speed internal expansion slot used mainly for storage.
Purpose
Provides very fast data transfer for SSDs.
Common Uses
- NVMe SSDs
- SATA-based M.2 SSDs
- Wi-Fi and Bluetooth cards (some systems)
M.2 Key Types
- Key B
- Key M
- Key B+M
These keys control compatibility and supported speeds.
Interface Types
- SATA M.2 (slower)
- PCIe / NVMe M.2 (much faster)
Exam Notes (M.2)
- M.2 is not the same as SATA, even if SATA-based
- NVMe uses PCIe lanes
- No cables required
- Mounted directly onto motherboard
Quick Exam Comparison Table
| Connector | Used For | Modern or Legacy |
|---|---|---|
| PCI | Older expansion cards | Legacy |
| PCIe | Graphics & expansion cards | Modern |
| SATA | HDD/SSD/Optical drives | Modern |
| eSATA | External storage | Legacy |
| Power connectors | Power delivery | Essential |
| Headers | Front panel & internal ports | Essential |
| M.2 | High-speed SSDs | Modern |
Key Exam Tips to Remember
- PCIe x16 is used for graphics cards
- SATA is data only
- M.2 NVMe is faster than SATA
- Power connectors are not interchangeable
- Headers connect case components
- PCI is obsolete
