COMPTIA A+ Core 1 SEC 3

What is the primary role of a motherboard?

Central printed circuit board (PCB) that acts as the backbone/hub; contains principal components and provides connectors for CPU, RAM, storage, expansion cards, and peripherals; enables communication between all parts.

What are the four basic computer functions (mnemonic)?

IPOS – Input (keyboard/mouse/touch), Processing (CPU/GPU), Output (monitor/speakers/printer), Storage (volatile = RAM/cache; non-volatile = HDD/SSD).

Volatile vs. non-volatile storage examples and behavior on power loss

Volatile (temporary): RAM, CPU cache – data lost when power off. Non-volatile (persistent): HDD, SSD, USB drives – data retained without power.

Motherboard speed measurement and typical ranges

Measured in MHz or GHz. Fast/volatile components (CPU cache, RAM) use GHz; slower/non-volatile (HDD/SSD) use MHz.

Why is form factor important when choosing a motherboard?

Determines physical size, shape, layout, compatible case, PSU, number/type of expansion slots, RAM slots, and storage connectors. Choose motherboard first – everything else depends on it.

ATX (full-size) key characteristics

Largest standard; up to 7 expansion slots; slots parallel to shorter side; rear port cluster; requires large tower case.

microATX key characteristics and compatibility

Square, smaller than full ATX; up to 4 expansion slots; fits in full ATX cases (same screw holes); same rear ports and slot orientation as ATX.

Mini-ITX key characteristics and compatibility

Small square; only 1 expansion slot; fits in ATX cases (same screw holes); commonly used for small form-factor builds.

Which form factors share the same mounting holes?

Full ATX, microATX, and Mini-ITX all use the same screw hole pattern → backward compatible with larger ATX cases.

Intel desktop socket type and pin location

LGA (Land Grid Array) – pins on the motherboard, contact pads on the CPU.

AMD desktop socket type and pin location

PGA (Pin Grid Array) – pins on the CPU, holes on the motherboard.

What mechanism is used for safe CPU installation on both Intel and AMD sockets?

ZIF (Zero Insertion Force) lever – lift to open, align CPU, lower lever to lock without damaging pins.

Mobile device CPU installation difference

CPUs are soldered directly to the motherboard → not upgradable (unlike desktop sockets).

Hyper-Threading / SMT

Allows a single core to execute multiple threads simultaneously; Intel = Hyper-Threading, generic/AMD = SMT; improves multitasking if software supports it.

Symmetric Multiprocessing (SMP)

Multiple physical CPUs (separate packages) sharing workload; requires multi-socket motherboard, identical CPUs, and OS support (rare in consumer desktops).

Multi-core vs. single-core

Multi-core = multiple processing units inside one CPU package; OS treats as one CPU but distributes tasks → better multitasking than single-core.

Virtualization support extensions (Intel and AMD)

Intel = VT (with EPT/SLAT); AMD = AMD-V (with RVI/SLAT); enables efficient hardware-assisted virtualization for running VMs.

x86 (32-bit) limitations

Max 4 GB RAM; runs only 32-bit software; legacy, rarely used today.

x64 (64-bit) advantages

Supports far more than 4 GB RAM; runs both 32-bit and 64-bit software; dominant in modern desktops/laptops.

ARM architecture key advantages and common uses

Lower power consumption, less heat, better battery life; used in mobile devices, wearables, Chromebooks, newer Apple Macs, some Windows devices.

Main power connector from PSU to motherboard

24-pin ATX main power (powers motherboard, RAM, expansion cards, fans).

Separate CPU power connector

8-pin (or 4+4-pin) CPU power – dedicated high-power supply for the CPU only.

Common storage connectors on motherboard

SATA (data = 7-pin L-shaped; power separate 15-pin from PSU); M.2 (flat slot for NVMe SSDs, secured with screw).

Purpose of CMOS battery

Small coin-cell battery; retains BIOS/UEFI settings when system is off (replace if date/time resets on boot).

Common rear I/O port colors and uses

USB 2.0 = black; USB 3.x = blue; high-speed/red/Type-C = 10+ Gbps; PS/2 = legacy keyboard/mouse (purple/green); RJ45 = Ethernet.

Modern dominant expansion slot type

PCIe (PCI Express) – point-to-point serial; versions increase speed; x1 (short, low bandwidth), x16 (long, high bandwidth for GPUs).

PCIe slot power limits

Standard slots = up to 25W; dedicated x16 GPU slots = up to 75W.

PCIe slot compatibility rules

Smaller card (e.g., x1) works in larger slot (e.g., x16) at full smaller speed; larger card in smaller slot possible but reduced speed (not recommended).

Common expansion card types and typical slots

Graphics/GPU → PCIe x16; Sound, NIC, Wi-Fi, storage controller → PCIe x1; Video capture → PCIe x1/x4; Riser cards → for low-profile cases.

Legacy expansion slot types (know names only)

PCI (old parallel, slow); PCI-X (faster 64-bit); AGP (dedicated old graphics) – all obsolete.