On the CompTIA A+, you should be able to compare and contrast the specifications of various types of RAM. These are the types of RAM you should be familiar with for your exam.
DDR (Double Data Rate): the industry standard for RAM; 184-pin DIMM, and 200- or 172-pin SO-DIMM
DDR2: faster than DDR and has less power consumption; comes in 240-pin DIMM and 200-pin SO-DIMM
DDR3: faster than DDR2 and has 30% less power consumption; comes in 240-pin DIMM and 204-pin SO-DIMM
SODIMM: RAM form factor found commonly in laptops; comes in 100-, 144-, 200-, 204-, and 260-pin configurations
DIMM (Dual Inline Memory Modules): configured in either 168 or 184 pins; both sides of DIMM chip used to provide connection to the socket, which effectively doubles the number of electrical connections; replaced older SIMM chip having the redundant connections on either side of the device
Parity vs. Non-Parity: refers to the ability to identify errors within the memory
ECC vs. non-ECC: refers to the ability to identify and resolve errors within the memory
RAM Configurations (single/double/triple channel): refers to using multiple identical sticks of RAM in paired slots, which increases the memory throughput
Single Sided vs. Double Sided: refers to which sides of memory module have memory chips
Buffered vs. Unbuffered: also known as “registered” memory; buffer between the memory and the controller; used on higher tier systems
Different RAM modules and specifications are not compatible with each other, although many of them share the same number of pins. Always check your motherboard documentation to find out which types of RAM are compatible with your system.
PC Expansion Cards
Expansion cards add additional functionality to your PC that were not previously there. You should be comfortable with installing and configuring the following expansion cards:
- sound cards
- video cards
- network cards
- USB cards
- firewire cards
- thunderbolt cards
- storage cards
- modem cards
- wireless/cellular cards
- TV tuner cards
- video capture cards
- riser cards
For the exam, you should be well-versed with the various types of storage devices and be comfortable with the installation and configuration procedures for each. Storage devices are categorized as follows:
CD-ROM: read only memory, stores up to 700MB of data
CD-RW: optical storage the same as CD-ROM, except it can be rewritten multiple times
DVD-ROM: read only memory; stores up to 4.7GB of data
DVD-RW: same storage capacity as DVD-ROM, except it can be rewritten multiple times
DVD-RW DL: dual-layer version of DVD-RW, nearly doubling the capacity to 8.5GB
Blu-ray: newer storage format, allowing storage up 25GB
BD-R: Blu-ray recordable format, allowing you to write data to it
BD-RE: Blu-ray recordable/erasable format, allowing you to write data to it more than once
Magnetic Hard Disk Drives
The designations of 5,400,7,200 and 10,000 refer to the rotational speed of the platter inside the hard drive. Speeds vary among different drives, but generally, the faster the rpm, the faster response time in reading and retrieving data.
Hot Swappable Drives
Hot swappable drives can be inserted or removed in real time, while the system is powered on. A common type of drive of this type is a USB.
Solid State/Flash Drives
Compact Flash: largest in physical size of the card type memory hardware
SD: Secure Digital format of flash that is very popular in modern times
Micro SD: flash type card that is used in small mobile devices and can be inserted into Mini SD cards for modularity or multipurpose use
Mini SD: flash type card that is used in small mobile devices, similar to micro SD
xD: flash card type typically found in older digital cameras
SSD: alternative to a standard hard disk drive; far superior, in that it is a form of flash memory
Hybrid: known as a solid-state hybrid drive (SSHD) and combines a traditional hard drive with a solid state drive; SSD is typically there for ease of caching data; more cost effective than a full-blown SSD
eMMC: flash memory type chip installed in mobile phones
RAID 0: offers striping of data only; no redundancy; good performance
RAID 1: offers mirroring of data only; requires more storage space to store full copies of data
RAID 5: offers striping with parity; minimum of three drives; ability to calculate missing data and rebuild
RAID 10: offers striping and mirroring for full redundancy; minimum of four drives
A tape drive is good for archiving data over extended periods of time, at a low cost.
The CPU functions as the brain of the computer, and it comes in many different types of formats. You should be familiar with all of these common socket types:
- Intel 775, 1155, 1156, 1366, 1150, and 2011
- AMD AM3, and AM3+
- FM1, FM2, and FM2+
There are several important characteristics of CPUs that are important to consider. Know about CPUs in terms of these:
- Most modern speeds are listed in gigahertz, which is the overall clock speed of that component.
- Most modern CPUs have multiple cores in one physical component. This means a quad core CPU essentially has four cores inside one component.
- A cache is extremely fast memory and enables the CPU to process a larger amount of information, depending on the size of the cache.
Hyperthreading allows you to increase the efficiency of your CPU, with gains of 15% to 30% over non-hyperthreaded processing.
- Intel and AMD both offer virtualization support by moving some of the virtualization functions from the software to the hardware for better performance.
- The terms 32-bit and 64-bit refer to the way a computer’s processor (also called a CPU), handles information. The 64-bit version of Windows handles large amounts of
random access memory (RAM) more effectively than a 32-bit system.
- An integrated GPU allows for graphics processing to be directly embedded with the CPU.
- The non-execute bit allows for hardening of the CPU by segmenting areas where code is needed to run and, for protection, disallowing it to run anywhere else.
- Heat sinks are positioned on top of components that get really hot. They draw the heat out onto the edges of the sink, called the fins.
- Fans are attached to the top of heat sinks to create what is referred to as a cooler. They can also be optionally attached to the case to increase air circulation. Fans are designed to pull cool air from the front of the system and exhaust it out the rear.
- Thermal paste is a heat-conductive substance that is applied between the surface of the CPU and the bottom of the heat sink. Know the proper procedure to apply the paste in a thin coating. The paste is designed to fill in the microscopic grooves on the metal surfaces that would trap air causing hot spots.
- Liquid cooling uses liquid piped to devices such as the CPU, Northbridge, etc. to cool the device. The liquid is circulated through the system and exits to an external radiator that cools it and recirculate it back through the system.
- Fanless devices use passive cooling with heat sinks only. Typically these device use minimal power. A video streaming device is an example.