Page 1 901 Hardware Study Guide for the CompTIA® A+ exam

How to Prepare for the Hardware Questions on the CompTIA A+ 901 Test

General Information

When you take the CompTIA A+ 901 certification test, you will find about 34% of the questions cover hardware. Most of the hardware questions simply involve recall of equipment and procedures. About 20% of them, however, require you to study a given scenario and apply the best solution.

This study guide should give you an idea of what to expect in terms of content, but it may not contain absolutely all of the content covered in the exam. Test producers say that the content is constantly being reviewed and revised, but this is the latest version. You are encouraged to use this guide as a starting point for your studies.

BIOS/UEFI Tools on a PC

The BIOS is, arguably, one of the most important aspects of a computer. You need to have a good understanding of system BIOS and how to modify the settings. Understand the importance of selecting the proper boot sequence and how BIOS provides low-level drivers that allow the operating system to interact with various hardware components. Comprehend the various stages in the boot sequence, the system POST, and the role BIOS plays in loading the operating system. The CompTIA A+ questions about BIOS require that you assess a scenario to be able to choose the best answer.

Firmware Upgrades

Always check the version of the BIOS you are using before doing an upgrade. This can be found in your system information utility, or by typing msinfo32 into the cmd prompt. Most manufacturers offer BIOS upgrades directly from their website, as a simple download, and it is a very straightforward process. Just download the correct file, based on the type of system you have, and run the update to begin the installation. This entire procedure is known as flashing the BIOS.

BIOS Components

When you are inside your BIOS, you will have the ability to view the type and quantity of memory available, the type of hard drive or solid-state drive in use, and the type of CPU. You will also have the option to view the type of optical drive installed and have the ability to disable/enable the component.

BIOS Configurations

Here are some important points to remember about BIOS configurations:

  • The boot sequence tells the BIOS where to look to load the operating system. It will proceed down the list in the order configured, until it finds an operating system to load.
  • Many of the device components are able to be enabled or disabled in the BIOS, including optical drives and storage devices.
  • The system date/time is displayed within the BIOS once you have accessed it. You will also be able to modify it from this location as well.
  • You are able to view and adjust your clock speed to run at a higher or lower frequency within the BIOS as well. This is typically found in one of the advanced settings.
  • Many BIOS systems offer virtualization support for access through applications like VMware or Hyper-V. Currently, VirtualBox does not offer BIOS integration within a Windows environment.
  • You are able to secure access to the BIOS as well as the operating system by adding passwords. You also need to know the procedures for deleting these passwords.
  • You are able to secure access to the BIOS, or to the operating system, by setting certain passwords from within the BIOS. These security measures require a password at startup in order to load the operating system or make changes to the BIOS.
  • Lojack is another security measure, which allows your computer to be tracked in the event it is physically stolen. It also offers remote shutdown and keylogger functionality.
  • Trusted Platform Module (TPM) is an additional security measure that can encrypt the contents of a storage device, or harden already in-place encryption techniques such as BitLocker and Secure Boot.

Built-in Diagnostics

BIOS almost always includes pre-built in diagnostic software to assist with troubleshooting hardware components. This is accessible directly from the BIOS and requires no additional software to be downloaded.


Within the BIOS, typically the advanced section, you will find various monitoring information available for the temperature, fan speeds, voltage, and bus speed. The clock utility can be found usually when you first enter the BIOS. Some computer cases also provide support for intrusion notification. When the case is opened, the CMOS can log and notify the user, typically on the next boot-up.

The Motherboard

The motherboard provides the circuitry by which all parts of a computer communicate with each other, from the processor to the power supply. Every part of a computer interacts with the motherboard in some fashion.


  • ATX stands for Advanced Technology Extended and is the most common motherboard you will see in desktops.
  • Older ATX variants contain a 20-pin Molex power connection, while newer models contain the 24-pin Molex power connection.
  • Micro-ATX is a little bit smaller than the ATX and does not have as much expansion ability.
  • ITX is a significantly smaller form factor board and was created by VIA Technologies.
  • Mini-ITX is the largest of the three ITX form factors, with a size of 6.7 by 6.7 inches. It is also the most popular.

Expansion Slots

  • PCI stands for Peripheral Component Interconnect and was introduced by Intel in the 1990s. This replaced older 8- and 16-bit expansion slots with a 32-bit slot.
  • PCI-X (Extended) incorporates a 64-bit data bus that was considerably faster than PCI slots, but because of the overall size of the bus, it was difficult to incorporate onto the motherboard.
  • PCIe (Express) is the newest expansion slot being used in modern computers. PCIe sends data in a serial stream at higher speeds than conventional PCI. These serial streams are referred to as lanes.
  • Mini-PCI slots were those modified to be applied to laptops. They use lower power and lie flat.

RAM Slots

There are several different RAM slots, with DIMM (dual inline memory module) being used in desktops, SO-DIMM (small outline) being used in laptops, and Micro-DIMM, which is being used in smaller mobile equipment.

CPU Sockets

The types of major sockets in use include the ZIF (zero force insertion). Be aware of the various configurations like PGA (pin grid array), SPGA (staggered pin grid array), and LGA (land grid array).


Be aware of the function of the chipset. The Northbridge, which interfaces directly with the CPU through the front-side bus, handles high-speed connections to memory and video as well as creating the connection to the Southbridge. The Southbridge handles I/O functions and all other slower devices such as the hard drive, PCI bus, and Audio.

CMOS Battery

The CMOS (complementary metal oxide semiconductor) battery was originally used to maintain system settings stored in CMOS RAM, since it was volatile. It is also used to power the systems real-time clock. Over the years, CMOS RAM has been replaced by flash memory that does not require a battery to maintain data; however, the real-time clock still requires a battery. As a preparation for this test, you should know how to locate and replace the CMOS battery.

Power Connections

Common power connector types include SATA, Molex, ATX, and EPS.

Fan Connectors

Most fan types will connect to a 3- or 4-pin Molex connector on the motherboard.

Front/Top Panel Connectors

Your computer typically contains on-board connections for things like USB and audio. There is also a set of wires within the computer case that connect to a certain component on the motherboard. When these are connected, you will be able to use the buttons on your computer case to do things (e.g. power on/off the computer, reset the computer). These connections inside the case also make use of activity and power lights, which will show a visual indicator of CPU activity, or indicating that power is being brought to the computer.

Bus Speeds

Bus speed indicates how fast all of the components on your motherboard are able to communicate with each other. You need to be aware of the various bus speeds in a modern PC such as PCI, the speeds of PCIe lanes, and memory.

Reset Button

The front panel of a desktop PC has a reset button that performs a hard boot of the system. In the event you have misconfigured certain BIOS or CMOS settings, this button allows you to reset everything to factory configuration. Be sure you understand the difference between hard and soft boots.