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CompTIA A+ Hardware FAQ

Comprehensive answers to the most common questions about CompTIA A+ Domain 3.0 Hardware

What topics are covered in CompTIA A+ Domain 3.0 Hardware?

Domain 3.0 covers cables and connectors, RAM installation, storage devices, motherboards, CPUs, add-on cards, power supplies, printers, and troubleshooting hardware issues.

What is the difference between DDR3, DDR4, and DDR5 RAM?

DDR3, DDR4, and DDR5 are generations of RAM with different speeds, voltages, and physical notch positions. DDR3 runs at 1.5V, DDR4 at 1.2V, and DDR5 at 1.1V. Each generation is faster and more power-efficient than the previous one, and they are not physically compatible with each other due to different notch placements.

What is dual-channel vs single-channel RAM configuration?

Dual-channel uses two matched RAM sticks in specific slots (often same-colored slots) to double memory bandwidth. Single-channel uses one stick or unmatched configurations with half the bandwidth. Dual-channel typically provides 10-30% better performance, especially in integrated graphics and memory-intensive tasks.

What is ECC RAM and when is it needed?

ECC (Error Correcting Code) RAM can detect and correct memory errors automatically. It's primarily used in servers, workstations, and mission-critical systems where data integrity is paramount. ECC RAM requires motherboard and CPU support and is typically more expensive than non-ECC RAM.

What is the difference between SATA and NVMe SSDs?

SATA SSDs connect via the SATA interface (up to 600 MB/s) and are limited by the SATA protocol. NVMe SSDs connect directly to the PCIe bus through M.2 or PCIe slots, offering much faster speeds (up to 7,000 MB/s or more) with lower latency. NVMe is designed specifically for SSDs, while SATA was originally designed for hard drives.

What is the difference between M.2 SATA and M.2 NVMe?

Both use the M.2 form factor but different interfaces. M.2 SATA uses the SATA protocol (up to 600 MB/s), while M.2 NVMe uses PCIe lanes (up to 7,000+ MB/s). They have different keying (B-key, M-key, B+M-key) and are not always interchangeable. Check motherboard specifications for supported types.

What are the main RAID levels and their purposes?

RAID 0 stripes data across drives for performance but no redundancy. RAID 1 mirrors data for redundancy. RAID 5 stripes data with parity across 3+ drives for balance of performance and redundancy. RAID 10 combines mirroring and striping for both performance and redundancy, requiring at least 4 drives.

How do I know which CPU socket my motherboard has?

Check the motherboard manual, manufacturer's website, or product specifications. Intel uses LGA sockets (like LGA1700, LGA1200), while AMD uses AM sockets (like AM4, AM5) or TR4 for Threadripper. The socket type determines which CPUs are compatible with your motherboard.

What is the difference between ATX and ITX motherboards?

ATX motherboards are standard-sized (12 x 9.6 inches) with more expansion slots and features. Mini-ITX motherboards are much smaller (6.7 x 6.7 inches) designed for compact builds with fewer expansion slots. ATX offers more connectivity options, while ITX prioritizes small form factor.

What is the difference between PCIe x1, x4, x8, and x16 slots?

PCIe slot numbers indicate the number of data lanes. x16 slots (typically for GPUs) have 16 lanes offering maximum bandwidth. x8, x4, and x1 have progressively fewer lanes and less bandwidth. Cards can physically fit in larger slots (x1 card in x16 slot) but will only use the lanes they need.

How do I calculate the power supply wattage I need?

Add up the power consumption of your CPU (65-125W typically), GPU (75-350W+), motherboard (~50-80W), storage devices (~5-10W each), RAM (~3-5W per stick), and fans (~3-5W each). Add 20-30% headroom for efficiency and future upgrades. Use online PSU calculators for accuracy.

What is the difference between modular and non-modular power supplies?

Modular PSUs allow you to detach cables you don't need, improving airflow and cable management. Semi-modular PSUs have essential cables (24-pin, CPU) permanently attached with optional cables detachable. Non-modular PSUs have all cables permanently attached.

What is thermal paste and when should it be replaced?

Thermal paste (thermal compound) fills microscopic gaps between the CPU/GPU and heatsink to improve heat transfer. It should be replaced when reinstalling a cooler, when temperatures increase significantly (every 2-3 years), or when it becomes dry or cracked.

What is the difference between Cat5e, Cat6, and Cat6a cables?

Cat5e supports up to 1 Gbps at 100 meters. Cat6 supports up to 10 Gbps at 55 meters or 1 Gbps at 100 meters with better shielding. Cat6a supports 10 Gbps at 100 meters with superior shielding against interference. Higher categories have stricter specifications and better performance.

What is the difference between HDMI and DisplayPort?

Both carry digital video and audio. DisplayPort typically supports higher refresh rates and resolutions, has better multi-monitor support (daisy-chaining), and is royalty-free. HDMI is more common in consumer electronics and TVs. Modern versions of both (HDMI 2.1, DisplayPort 2.0) support 4K/8K and high refresh rates.

What is TPM and why is it required for Windows 11?

TPM (Trusted Platform Module) is a security chip that stores encryption keys, passwords, and certificates securely. Windows 11 requires TPM 2.0 for enhanced security features like BitLocker encryption and secure boot. It can be a discrete chip on the motherboard or integrated into the CPU (fTPM/PTT).

What is the difference between UEFI and legacy BIOS?

UEFI (Unified Extensible Firmware Interface) is the modern replacement for legacy BIOS. UEFI supports drives larger than 2TB, faster boot times, mouse support, network capabilities, and Secure Boot. Legacy BIOS is limited to MBR partitioning (2TB max) and basic keyboard navigation.

What is Secure Boot and should I enable it?

Secure Boot is a UEFI security feature that only allows digitally signed operating systems and bootloaders to run, preventing rootkits and bootkits. Enable it for Windows 10/11 and most modern Linux distributions for enhanced security. Disable it only if running older operating systems or unsigned bootloaders.

What are the differences between laser, inkjet, and thermal printers?

Laser printers use toner and heat (fuser) for fast, high-volume printing with low cost per page. Inkjet printers spray liquid ink for better color quality at lower initial cost but higher per-page cost. Thermal printers use heat-sensitive paper for receipts and labels with no ink/toner needed but special paper required.

What does the laser printer imaging process involve?

The laser printer imaging process has 7 steps: Processing (RIP converts data to bitmap), Charging (corona wire charges drum), Exposing (laser discharges specific areas), Developing (toner attracted to discharged areas), Transferring (toner transferred to paper), Fusing (heat and pressure fuse toner), and Cleaning (excess toner removed).

How can I prepare for the CompTIA A+ hardware section?

Review each section of this guide, use hands-on labs if possible, and take practice quizzes for Domain 3.0. Work with actual hardware components, practice cable identification, understand RAM installation, and learn troubleshooting methodologies. CompTIA emphasizes scenario-based questions, so practical experience is valuable.

Are there free resources for CompTIA A+ hardware study?

Yes, this guide provides free explanations, diagrams, and links to related A+ domains and practice quizzes. Additional free resources include manufacturer documentation, YouTube tutorials, Reddit communities (r/CompTIA), and practice exams on sites like ProfTIA.com.