Domain 1: Mobile Devices
- Laptop RAM uses SO-DIMM modules (DDR4 or DDR5), roughly half the length of a desktop DIMM, seated at an angle and then pressed flat to lock.
- Laptop storage is typically an M.2 NVMe SSD or 2.5 inch SATA drive; many thin ultrabooks solder storage directly to the motherboard, making it non-upgradeable.
- Bluetooth pairs nearby peripherals (headsets, keyboards, mice) over short range, NFC enables contactless payment and one-tap pairing, and GPS provides location services.
- Cellular data (LTE or 5G) gives a mobile device wide-area internet access; a mobile hotspot shares that connection with other devices over Wi-Fi, USB, or Bluetooth tethering.
- USB-C is the standard reversible charging and data port on current laptops and phones; it supports USB Power Delivery (PD) for fast charging and DisplayPort Alt Mode for external video.
- Docking stations and port replicators expand a laptop's I/O, adding extra displays, Ethernet, and USB ports through a single USB-C or Thunderbolt cable.
- Laptop displays use IPS, OLED, or older TN panel technology; a digitizer layered over the screen senses finger or stylus touch input.
- Laptop batteries are lithium-ion; avoid deep discharges and heat exposure to prolong lifespan, and replace a swollen battery immediately rather than continuing to use it.
- Mobile device synchronization keeps contacts, email, photos, and app data consistent across devices through a cloud account or a direct wired connection.
- Airplane mode disables all radios at once (cellular, Wi-Fi, Bluetooth, GPS); Wi-Fi and Bluetooth can typically be re-enabled independently afterward.
- Field-replaceable laptop components commonly include the battery, RAM, storage, and keyboard, though many modern ultrabooks solder RAM and storage to the board.
Domain 2: Networking
- RJ45 (8P8C) connectors terminate twisted-pair Ethernet; Cat5e supports 1 Gbps and Cat6 supports 10GBASE-T over short runs, with a 100 meter (328 ft) maximum run length for copper.
- RFC 1918 private address ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16; NAT/PAT lets many private hosts share a single public IP.
- 169.254.0.0/16 is APIPA (link-local), self-assigned when no DHCP server responds and never routed; 127.0.0.0/8 is the loopback range and never appears on the wire.
- DHCP uses the DORA exchange (Discover, Offer, Request, Acknowledge) over UDP ports 67 (server) and 68 (client) to hand out an IP, subnet mask, gateway, DNS, and lease time.
- Key well-known ports to memorize: HTTP 80, HTTPS 443, SSH 22, Telnet 23, FTP 20/21, SMTP 25, DNS 53, DHCP 67/68, and SMB 445.
- In the crowded 2.4 GHz Wi-Fi band, use only the non-overlapping channels 1, 6, and 11 to avoid co-channel interference between neighboring access points.
- ping sends ICMP echo requests to test reachability and latency, and tracert/traceroute maps each hop along the path to a destination.
- auto-MDIX lets modern switch ports automatically detect and swap transmit/receive pairs, so crossover cables are no longer needed between like devices.
- Managed switches add VLANs, QoS, SNMP monitoring, and port mirroring for traffic segmentation and visibility; unmanaged switches offer none of that.
- Routers operate at OSI Layer 3 and forward packets between IP networks by routing table lookup; switches operate at Layer 2 and forward frames by MAC address.
- Fiber optic cabling (single-mode for long haul, multimode for shorter runs) is immune to electromagnetic interference and supports much longer distances than copper.
Domain 3: Hardware
- SSDs use NAND flash with no moving parts for sub-millisecond access and shock resistance; NVMe SSDs run over PCIe lanes and far exceed SATA's roughly 550 MB/s ceiling.
- M.2 slots are keyed B (SATA only), M (PCIe NVMe), or B+M; an NVMe M-key drive will not fit or function in a SATA-only B-key slot.
- DDR5 and DDR4 desktop DIMMs are not interchangeable with each other or with prior generations; the notch position and pin count differ so an incompatible module physically will not seat.
- Dual-channel memory requires matched modules installed in the correct paired (often same colored) slots per the motherboard manual; the wrong slots drop the system to single-channel bandwidth.
- Power supply sizing: total the rated wattage of every component, add roughly 20-30 percent headroom, and choose an 80 PLUS-rated unit with the connectors (PCIe 6/8-pin or 12VHPWR) the GPU requires.
- The PSU converts AC mains (120V/240V) into the DC rails a PC needs (+12V, +5V, +3.3V) plus a standby rail that keeps the board powered enough to respond to the power button.
- RAID levels to know: RAID 0 stripes for speed with no redundancy, RAID 1 mirrors, RAID 5 stripes with distributed parity to survive one drive failure, and RAID 10 mirrors then stripes for both redundancy and performance.
- DisplayPort and HDMI carry digital video and audio; converting either to analog VGA requires an active, powered adapter that performs digital-to-analog conversion, not a passive pin adapter.
- Overheating and thermal throttling are commonly fixed by clearing dust from vents and fans, confirming case airflow direction, and reapplying thermal paste between the CPU/GPU and heatsink.
- Laptops with switchable or hybrid graphics use the low-power integrated GPU on battery and the discrete GPU when plugged in or under heavy load.
- exFAT removes FAT32's 4 GB file size and roughly 2 TB volume limits and is the common cross-platform choice for large removable media, while NTFS remains required for the Windows system volume.
Domain 4: Virtualization and Cloud Computing
- A hypervisor abstracts physical hardware into virtual machines; Type 1 (bare-metal) hypervisors like ESXi or Hyper-V run directly on hardware, while Type 2 hypervisors run on top of a host OS.
- Virtualization enables server consolidation and workload isolation, letting one physical host run multiple independent guest operating systems.
- Containers (for example Docker) share the host OS kernel for lightweight, fast-starting, isolated application environments, unlike VMs, which each run a full guest OS.
- Cloud service models: SaaS (provider manages the entire application, e.g. Microsoft 365), PaaS (provider manages the platform and runtime), and IaaS (the customer manages the OS and up, provider manages the hardware).
- Cloud deployment models include public (shared infrastructure), private (dedicated to one organization), hybrid (a mix of both), and community (shared among organizations with common requirements).
- Rapid elasticity lets cloud resources scale up or down automatically to match demand, and metered pay-as-you-go billing charges only for resources actually consumed.
- A VM snapshot captures a point-in-time image of a virtual machine's disk and memory state, enabling a quick rollback if a change goes wrong.
- VM resource planning covers vCPU count, allocated RAM, storage provisioning (thin or thick), and a network connection method (bridged, NAT, or host-only).
- Cloud cost control practices include right-sizing oversized instances, scheduling non-production resources to shut down outside business hours, and moving cold data to lower-cost archive storage tiers.
- High availability in the cloud is achieved by distributing workloads across multiple availability zones or regions so a single data center failure does not cause an outage.
Domain 5: Hardware and Network Troubleshooting
- The CompTIA troubleshooting methodology: identify the problem, establish a theory of probable cause, test the theory, establish a plan of action, implement the solution, verify full functionality and apply preventive measures, and document findings and outcomes.
- POST beep codes signal hardware failures (commonly bad RAM or a GPU issue) before the display initializes; consult the motherboard or BIOS vendor's beep code chart to interpret them.
- Always wear an ESD anti-static wrist strap and use proper grounding before handling internal components, since electrostatic discharge can silently damage sensitive chips.
- A negotiated link speed lower than expected (for example 100 Mbps instead of 1 Gbps) usually points to a damaged cable, a duplex mismatch, or cabling rated below the required category.
- Intermittent outages or broadcast storms on a switched network can indicate a switching loop; check cabling and port status and confirm Spanning Tree Protocol (STP) is enabled.
- Cable runs near motors, fluorescent lighting, or power lines suffer electromagnetic interference (EMI); replace them with shielded (STP) cabling routed away from the source, or use fiber, which is immune to EMI.
- Slow boot or performance issues are diagnosed by checking S.M.A.R.T. drive health and free disk space, disabling unnecessary startup programs, and confirming the memory channel mode in BIOS/UEFI.
- Sustained high CPU or GPU temperatures that cause clock speeds to drop indicate thermal throttling from inadequate cooling; a process stalled on slow I/O points to the storage subsystem instead.
- Common printer symptoms: faded or light print output points to low toner or a failing imaging drum on a laser printer, while vertical lines or streaks often indicate a dirty or scratched drum.
- No-boot troubleshooting isolates whether the fault is power (dead PSU, no fans spinning), display (no POST beep but fans spin), or storage (POST completes but the OS fails to load).
- Weak Wi-Fi signal or intermittent wireless drops are commonly resolved by relocating the access point away from interference sources, changing channels, or adding an additional AP for coverage.
CompTIA A+ Core 1 (220-1201) exam tips
- Memorize well-known port numbers and RFC 1918 private ranges cold - they are fast, easy points if you have them instantly.
- Learn the seven-step CompTIA troubleshooting methodology in exact order; scenario questions often ask which step comes next.
- Expect performance-based questions (PBQs) early in the exam; they take the most time, so consider flagging one and returning to it rather than losing time on later multiple-choice items.
- Know connector and cable types by sight (RJ45, USB-C, M.2 keying, DisplayPort/HDMI) since several questions describe or show a physical connector.
- Read for the BEST or FIRST answer when multiple options look technically valid; questions often hinge on the safest or earliest correct step, such as ESD precautions before touching hardware.
- Build hands-on familiarity with RAID levels and hypervisor types (Type 1 vs Type 2) since these concepts are tested with applied scenarios, not just definitions.
Study guide FAQ
How many exams do I need to pass, and how does Core 1 differ from Core 2?
You must pass two separate exams to earn the CompTIA A+ certification: Core 1 (220-1201) and Core 2 (220-1202). Core 1 covers mobile devices, networking, hardware, virtualization and cloud computing, and hardware and network troubleshooting. Core 2 covers operating systems, security, software troubleshooting, and operational procedures. Each exam is scored and passed independently.
What is the passing score, and how long is the exam?
CompTIA A+ Core 1 (220-1201) has a maximum of 90 questions with a 90 minute time limit, and requires a scaled score of 675 out of 900 to pass. Questions are a mix of multiple-choice and performance-based simulations (PBQs).
Are these official CompTIA questions?
No. These are independent practice questions written to reflect the topics and style of the CompTIA A+ Core 1 (220-1201) objectives. They are a study aid, not actual exam content, and are not affiliated with or endorsed by CompTIA.
Who is CompTIA A+ Core 1 designed for?
A+ targets entry-level IT support technicians such as help desk agents, desktop support staff, and field service technicians. There is no required prerequisite certification, though CompTIA recommends some hands-on exposure to PC hardware and networking before attempting the exam.
Do I need to take Core 1 and Core 2 at the same time or in a specific order?
No. You can take Core 1 and Core 2 in either order and on different dates; the certification is only awarded once you have passed both.
What topics make up the largest share of the Core 1 exam?
Hardware and hardware/network troubleshooting make up the largest portions of Core 1, followed by networking; mobile devices and virtualization and cloud computing are smaller but still tested domains.
Official exam sources
The domain names and weightings on this page follow the published exam blueprint. Each source below records what it confirmed and when it was read, so the split can be checked rather than taken on trust.
- CompTIA A+ Core 1 (220-1201) certification pagelink and content verified 8 September 2026Every figure on this guide, with nothing to correct. "Exam series code: 220-1201 (Core 1)"; "Number of questions: Maximum of 90 per exam" including multiple-choice, drag-and-drop and performance-based; "Length of test: 90 minutes"; "Passing score: A+ Core 1: 675 (on a scale of 900)", which is our 675 / 900 label; "Recommended experience: 12 months of hands-on experience in an IT support specialist job role" - recommended, not required. Five domains totalling 100%: Mobile devices 13%, Networking 23%, Hardware 25%, Virtualization and cloud computing 11%, Hardware and network troubleshooting 28% - the domain weights used by CertGrid practice exams exactly. Read through a rendered browser; the top-level /certifications/a/ page shows only the two-exam summary, which is why an earlier pass recorded this one as unrendered - the per-exam V15 pages carry the detail.