CompTIA A+ Core 1 — All Questions

Which memory technology is most commonly used as the main system RAM in a modern desktop computer?

• a.GDDR video memory
• b.DDR SDRAM DIMMs✓
• c.NAND flash chips
• d.EEPROM

Modern desktops use DDR SDRAM installed as DIMM modules for main system memory. NAND flash is used for SSDs, GDDR is dedicated video memory on graphics cards, and EEPROM stores small amounts of firmware data.

A technician wants dual-channel memory performance. What is the correct way to install two matching DIMMs?

• a.Populate the matching color-coded slots specified by the board✓
• b.Install one DDR4 and one DDR5 module
• c.Stack them in the first two physical slots only
• d.Place both in adjacent slots regardless of color

Dual-channel mode requires identical modules placed in the color-coded slot pairs the motherboard designates, usually slots 1 and 3 or 2 and 4. Mixing memory generations is impossible because the slots are keyed differently, and simply using adjacent slots may not enable dual channel.

Which storage interface offers the highest sequential throughput for a consumer SSD?

• a.NVMe over PCIe✓
• b.PATA/IDE
• c.SATA III
• d.USB 2.0

NVMe drives communicate over the PCIe bus and greatly exceed the roughly 600 MB/s ceiling of SATA III. USB 2.0 and legacy PATA are far slower and are not used for high-performance internal storage.

What physical form factor is typical for an NVMe solid-state drive installed directly on a motherboard?

• a.PCIe x16 graphics slot
• b.2.5-inch drive bay
• c.5.25-inch bay
• d.M.2 slot✓

Consumer NVMe SSDs commonly use the M.2 gumstick form factor that plugs into a dedicated M.2 slot on the board. The 2.5-inch bay is for SATA SSDs and laptops, while the x16 slot is intended for graphics cards.

A power supply is rated 80 PLUS Gold. What does this rating describe?

• a.The number of PCIe connectors
• b.Physical size of the unit
• c.Maximum wattage output
• d.Energy efficiency at typical loads✓

The 80 PLUS certification tiers (Bronze, Gold, Platinum, etc.) describe how efficiently a PSU converts AC to DC at various load levels. It does not indicate the wattage, connector count, or physical dimensions of the unit.

Which connector supplies dedicated power to a high-end graphics card?

• a.SATA power connector
• b.24-pin ATX
• c.6/8-pin PCIe power connector✓
• d.4-pin Molex to the CPU

Discrete GPUs draw supplemental power through 6-pin or 8-pin PCIe power connectors from the PSU. The 24-pin feeds the motherboard, SATA power feeds drives, and the CPU uses a separate 4/8-pin EPS connector.

What is the primary purpose of thermal paste between a CPU and its heat sink?

• a.To glue the heat sink permanently
• b.To insulate the CPU electrically
• c.To prevent static discharge
• d.To fill microscopic gaps and improve heat transfer✓

Thermal paste fills the tiny air gaps between the CPU integrated heat spreader and the cooler base, improving thermal conduction. It is not an adhesive, an electrical insulator, or an anti-static measure.

Which expansion slot is used by a modern discrete graphics card?

• a.AGP
• b.PCI 32-bit
• c.PCIe x16✓
• d.ISA

Current graphics cards use the PCI Express x16 slot for maximum bandwidth. PCI, AGP, and ISA are legacy interfaces no longer used for new GPUs.

A motherboard's CMOS settings and clock reset every time the PC is unplugged. What is the most likely cause?

• a.Failed CPU
• b.Bad RAM
• c.Depleted CMOS battery✓
• d.Corrupt operating system

The coin-cell CMOS battery (typically a CR2032) maintains BIOS/UEFI settings and the real-time clock when power is removed. When it dies, settings and the clock reset on every power loss.

Which RAID level mirrors data across two drives for redundancy without striping?

• a.RAID 0
• b.RAID 1✓
• c.RAID 10
• d.RAID 5

RAID 1 writes identical copies of data to two drives, providing fault tolerance if one drive fails. RAID 0 stripes without redundancy, RAID 5 uses striping with parity, and RAID 10 combines mirroring and striping.

How many drives are minimally required to build a RAID 5 array?

• a.Four
• b.One
• c.Three✓
• d.Two

RAID 5 distributes parity across all members and needs a minimum of three drives. It can survive the loss of a single drive by rebuilding from parity information.

Which display connector can carry both high-resolution video and audio over a single cable and is common on modern GPUs?

• a.PS/2
• b.VGA
• c.DVI-D
• d.DisplayPort✓

DisplayPort carries digital video and audio and supports high resolutions and refresh rates. VGA is analog video only, DVI-D carries video but not audio, and PS/2 is a keyboard/mouse connector.

What does ECC memory provide that standard memory does not?

• a.Lower power draw
• b.Built-in encryption
• c.Detection and correction of single-bit errors✓
• d.Faster clock speeds

ECC (error-correcting code) memory can detect and correct single-bit errors, which is valuable in servers and workstations. It does not inherently run faster, use less power, or encrypt data.

A technician needs to connect four SATA hard drives but the case lacks power connectors. Which cable adapts available power?

• a.USB-to-Ethernet adapter
• b.Molex-to-SATA power adapter✓
• c.DVI-to-VGA adapter
• d.HDMI splitter

A Molex-to-SATA power adapter converts a legacy 4-pin Molex lead into a SATA power connector for drives. The other adapters handle video or network signals, not drive power.

Which CPU feature allows a single physical core to handle two threads simultaneously?

• a.Simultaneous multithreading (Hyper-Threading)✓
• b.Integrated graphics
• c.Thermal throttling
• d.Overclocking

Simultaneous multithreading, marketed by Intel as Hyper-Threading, lets one core process two instruction threads to improve utilization. Overclocking raises clock speed, throttling reduces it for heat, and integrated graphics is a separate GPU feature.

What is the standard number of pins on the main ATX motherboard power connector?

• a.4 pins
• b.20 pins only
• c.8 pins
• d.24 pins✓

The modern main ATX power connector has 24 pins (a 20-pin base plus a 4-pin extension). The separate CPU EPS connector uses 4 or 8 pins.

Which type of cooling uses a pump, radiator, and liquid to move heat away from the CPU?

• a.Case fan only
• b.Thermal pad
• c.Passive heat sink
• d.Closed-loop liquid cooler (AIO)✓

An all-in-one (AIO) closed-loop liquid cooler circulates coolant through a CPU block to a radiator with fans. A passive heat sink, single case fan, or thermal pad rely on simpler conduction and airflow.

A user reports the PC powers on but there is no display and a repeating beep code sounds. What should the technician consult?

• a.The printer manual
• b.The motherboard/BIOS beep code documentation✓
• c.The Wi-Fi router settings
• d.The event log in Windows

POST beep codes are defined by the BIOS/motherboard vendor and point to hardware faults such as RAM or GPU problems. Because there is no display and the OS has not loaded, Windows logs are unavailable.

Which connector standard is commonly used for internal case front-panel USB 3.x headers?

• a.3.5mm TRS
• b.19/20-pin USB 3.0 header✓
• c.RJ45
• d.PS/2 mini-DIN

Front-panel USB 3.x ports connect to the motherboard through a keyed 19/20-pin internal header. RJ45 is for Ethernet, 3.5mm is audio, and PS/2 is a legacy input connector.

What is the main advantage of a solid-state drive over a traditional hard disk drive?

• a.Uses magnetic platters for redundancy
• b.Larger maximum capacity at lower cost
• c.No moving parts, faster access, and shock resistance✓
• d.Requires no data connection

SSDs store data in flash with no moving parts, giving faster access times and better durability against shock. HDDs still lead on cost per terabyte, but they rely on spinning magnetic platters.

Which component temporarily stores data the CPU is actively using and loses its contents when powered off?

• a.Optical disc
• b.BIOS ROM
• c.Hard drive
• d.System RAM✓

System RAM is volatile memory that holds active program data and is cleared when power is removed. Hard drives and optical discs are non-volatile storage, and BIOS ROM retains firmware.

A technician is asked to install a second GPU for more video ports. Which factor must be verified first?

• a.Number of USB drives
• b.Available PCIe slots and adequate PSU wattage/connectors✓
• c.Monitor cable color
• d.Keyboard layout

Adding a GPU requires a free PCIe x16 slot and a power supply with enough wattage and the correct PCIe power connectors. Peripheral details like cable color or USB drives are irrelevant to installation feasibility.

Which unit describes the rotational speed of a mechanical hard drive that affects its performance?

• a.Watts
• b.Gbps
• c.RPM✓
• d.MHz

Mechanical HDD performance is influenced by platter rotational speed measured in revolutions per minute (e.g., 5400 or 7200 RPM). MHz measures clock frequency, Gbps measures data rate, and watts measure power.

What is the correct anti-static precaution when handling internal PC components?

• a.Wear rubber gloves and touch nothing metal
• b.Work on a carpeted floor barefoot
• c.Rub the component to discharge it
• d.Use an anti-static wrist strap connected to a grounding point✓

An ESD wrist strap bonded to a proper ground equalizes potential and safely dissipates static that could damage components. Carpet increases static, rubbing generates it, and simply wearing rubber gloves does not ground you.

Which TCP port is used by HTTPS web traffic by default?

• a.25
• b.443✓
• c.21
• d.80

HTTPS uses TCP port 443 for encrypted web traffic. Port 80 is plain HTTP, port 21 is FTP control, and port 25 is SMTP email.

What port does standard unencrypted HTTP use?

• a.3389
• b.80✓
• c.53
• d.443

HTTP serves web pages over TCP port 80. Port 443 is HTTPS, 53 is DNS, and 3389 is Remote Desktop Protocol.

Which protocol translates human-readable domain names into IP addresses?

• a.SNMP
• b.DNS✓
• c.SMTP
• d.DHCP

DNS resolves names like example.com into IP addresses. DHCP assigns addresses, SMTP sends email, and SNMP monitors network devices.

Which service automatically assigns IP addresses, subnet masks, and gateways to clients?

• a.DNS
• b.DHCP✓
• c.FTP
• d.LDAP

DHCP leases IP configuration to clients automatically. DNS handles name resolution, FTP transfers files, and LDAP provides directory services.

Which Wi-Fi standard, also known as Wi-Fi 6, operates in both 2.4 GHz and 5 GHz bands with improved efficiency?

• a.802.11g
• b.802.11n
• c.802.11ax✓
• d.802.11ac

802.11ax (Wi-Fi 6) improves efficiency and capacity and works in both 2.4 GHz and 5 GHz. 802.11ac is 5 GHz only, while 802.11n and 802.11g are older standards.

Which class of IPv4 address is 192.168.1.0/24 considered?

• a.Public routable
• b.Loopback
• c.Private (RFC 1918)✓
• d.APIPA

The 192.168.0.0/16 range is private per RFC 1918 and is not routable on the public internet. Loopback is 127.0.0.0/8, and APIPA uses 169.254.0.0/16.

A client shows an IP address in the 169.254.x.x range. What does this indicate?

• a.A static public IP
• b.A successful DHCP lease
• c.An IPv6 link-local address
• d.APIPA — the client failed to reach a DHCP server✓

An address in 169.254.0.0/16 is APIPA, which a Windows host self-assigns when no DHCP server responds. It signals a DHCP problem rather than a normal lease.

Which port is used by the Remote Desktop Protocol (RDP)?

• a.23
• b.161
• c.22
• d.3389✓

RDP listens on TCP port 3389. Port 22 is SSH, port 23 is Telnet, and 161 is SNMP.

Which protocol provides secure encrypted command-line access to a remote device?

• a.HTTP
• b.FTP
• c.Telnet
• d.SSH✓

SSH encrypts remote shell sessions on port 22. Telnet, FTP, and HTTP all send data, including credentials, in clear text by default.

What is the primary function of a router in a network?

• a.Amplify Wi-Fi signal only
• b.Forward packets between different networks✓
• c.Store shared files
• d.Provide power over Ethernet

A router forwards packets between separate networks, such as a home LAN and the internet, using IP addressing. Signal boosting, PoE, and file storage are handled by other devices.

Which cable type is required for 10 Gigabit Ethernet over reasonable copper distances?

• a.Cat 3
• b.RG-6 coax
• c.Cat 6a✓
• d.Cat 5

Cat 6a supports 10 Gbps over 100 meters. Cat 5 and Cat 3 cannot reliably carry 10 Gbps, and RG-6 is coaxial cable used for video/cable modems.

Which device operates primarily at Layer 2 and forwards frames based on MAC addresses?

• a.Hub
• b.Router
• c.Switch✓
• d.Modem

A switch learns MAC addresses and forwards frames only to the correct port at Layer 2. A hub blindly repeats to all ports, a router works at Layer 3, and a modem modulates signals for the ISP link.

What does NAT allow a home network to do?

• a.Encrypt all traffic automatically
• b.Assign DNS names
• c.Increase Wi-Fi range
• d.Share one public IP among many private devices✓

Network Address Translation lets multiple internal devices share a single public IP address. It is not an encryption, range-extension, or naming service.

Which protocol and port combination is used to send email between mail servers?

• a.SMTP on 25✓
• b.IMAP on 143
• c.DNS on 53
• d.POP3 on 110

SMTP on TCP port 25 transfers email between servers. POP3 (110) and IMAP (143) are used by clients to retrieve mail, and DNS resolves names.

A subnet mask of 255.255.255.0 corresponds to which CIDR notation?

• a./8
• b./24✓
• c./16
• d./32

255.255.255.0 sets the first 24 bits as the network portion, written as /24. /16 is 255.255.0.0, /8 is 255.0.0.0, and /32 is a single host.

Which wireless frequency band generally offers longer range but lower maximum speed?

• a.5 GHz
• b.2.4 GHz✓
• c.60 GHz
• d.6 GHz

The 2.4 GHz band penetrates walls better and reaches farther but supports lower throughput and has more interference. Higher bands like 5 GHz and 6 GHz offer more speed over shorter distances.

Which connector terminates a twisted-pair Ethernet cable?

• a.SC
• b.RJ11
• c.BNC
• d.RJ45✓

Ethernet twisted-pair cables use 8-position RJ45 connectors. RJ11 is for telephone lines, BNC is coax, and SC is a fiber-optic connector.

What is the purpose of a default gateway in IP configuration?

• a.Assign IP leases
• b.Resolve domain names
• c.Filter spam
• d.Route traffic destined for other networks✓

The default gateway is the router address a host sends traffic to when the destination is on another network. DNS resolves names and DHCP assigns leases.

Which command-line tool displays a device's current IP configuration on Windows?

• a.tracert
• b.ipconfig✓
• c.nslookup
• d.ping

ipconfig shows the local IP address, subnet mask, and gateway on Windows. ping tests reachability, tracert maps the route, and nslookup queries DNS.

Which protocol is used to synchronize the clocks of devices across a network?

• a.SNMP
• b.SMTP
• c.NTP✓
• d.DHCP

The Network Time Protocol (NTP) keeps device clocks synchronized, typically over UDP port 123. SNMP monitors devices, SMTP sends email, and DHCP assigns IP configuration.

Which storage type is used in most modern laptops due to durability and speed?

• a.Optical drive
• b.Solid-state drive (M.2 or SATA)✓
• c.Tape drive
• d.5400 RPM hard drive

Modern laptops favor SSDs for their speed, low power draw, and resistance to shock from movement. Spinning drives, optical, and tape are largely obsolete in current portable designs.

A laptop battery no longer holds a charge and is swollen. What is the correct action?

• a.Keep using it until fully dead
• b.Freeze it overnight
• c.Puncture it to release gas
• d.Safely replace the battery and dispose of it properly✓

A swollen lithium-ion battery is a safety hazard and must be replaced and recycled through proper channels. Continuing to use, puncturing, or freezing it risks fire or rupture.

Which technology lets a smartphone make contactless payments when tapped at a terminal?

• a.GPS
• b.Infrared
• c.Bluetooth
• d.NFC✓

Near Field Communication (NFC) enables tap-to-pay over very short distances. Bluetooth pairs peripherals, GPS provides location, and infrared is a legacy line-of-sight link.

What does a laptop's inverter historically provide power to on older LCD screens?

• a.The webcam
• b.The trackpad
• c.The CCFL backlight✓
• d.The keyboard backlight

On older laptops the inverter supplied high voltage to the cold-cathode fluorescent (CCFL) backlight. Modern LED-backlit panels no longer need an inverter.

Which connector has become the common standard for charging and data on modern Android phones and many laptops?

• a.Micro-USB
• b.Mini-USB
• c.Lightning
• d.USB-C✓

USB-C is a reversible connector widely adopted for charging and data on Android devices and laptops. Micro-USB and Mini-USB are older, and Lightning is Apple-specific.

A user wants to sync a wireless headset to a phone. Which technology is used?

• a.Ethernet
• b.HDMI
• c.Bluetooth pairing✓
• d.NFC only

Bluetooth is used to pair and connect wireless audio devices to phones. NFC may initiate pairing on some devices but the audio link runs over Bluetooth; Ethernet and HDMI are wired.