A computer's central processing unit (CPU) is like the "brain" of the computer. The CPU carries out instructions by performing arithmetic and logical calculations.

Major Specifications

• Number of Cores
• More cores are generally better (quad-core is better than dual-core).
More cores provide improved performance in CPU intensive applications such as professional programs like Photoshop.
• Additional cores also improve performance in multitasking.
• Clock Speed
• Clock speed is the number of calculations per second.
• CANNOT be compared across different architectures because different architectures use different instructions.
• Some Intel CPUs come with turbo boost, allowing for increased computing power when needed and when factors such as system power allow.

Random Access Memory (RAM) acts as super fast temporary storage for the CPU; programs load necessary data from storage into RAM. The CPU then accesses the data on RAM to take advantage of the significant speed advantages of RAM over long-term storage. The RAM is analogous to the desk space in an office, it is the limiting factor determining how much 'stuff' can be running at one time. Data is only stored on RAM when the computer it is receiving power (i.e. the data on RAM will disappear when the computer is turned off).

Major Specifications

• Number of Pins
• Number of contacts on memory sticks (needs to match the number on the computer's motherboard)
• Frequency
• How many clock cycles can performed per second
• Latency
• Indicates how fast the memory reacts to a request to read or write data
• Lower latency is typically better
• This is commonly displayed as the CL number (ie CL9)
• Number of Modules
• More modules are typically better but have to match the motherboard
• SIMM - Single in-line memory module
• DIMM - Double in-line memory module
• Capacity
• How much data the memory can store
• Larger capacity is typically better

The video card or graphics processing unit (GPU) drives the computer's display. The GPU can also act as an extra processor when doing high resource calculations. There are two types of video cards:

• Integrated Cards - these cards are built into the computer's motherboard. They share the computer's memory causing slower computing while using graphics intensive tasks. Modern integrated graphics cards are fine for regular use (ie email, internet, etc) and thus are used in most laptops.
• Dedicated Cards - these cards are independent units from the computer's other components and have dedicated memory allocated for them within the unit. Typically dedicated graphics cards are better than integrated cards. They are most commonly found on desktop computers and are very important if users are doing serious gaming or using processing graphically intensive programs.

Major Specifications

• Graphics Chip
• This is the most important feature
• Typically the higher number in the chipset line is better (a Nvidia GeForce GTX 1070 is better than a 1060 but less powerful than a 1080) but not always. It is ussually best to research a specific chipset's performance running the user's desired programs.
• Memory
• The amount of memory dedicated to the video card
• More memory is needed if the user plans on using multiple displays or wishes to use high definition graphics in games

The screen that the computer displays information on.

Major Specifications

• Size
• The physical size of the monitor; measured diagonally
• Resolution
• The number of pixels in each dimension the monitor can display. More pixels allow for a crisper display (ie 2560x1600, 1920x1080 or 1080p, 1366x768)
• Response Time
• The time it takes to change a pixel from one color to the next
• Brightness
• Measure of the brightest white on the display
• Contrast Ratio
• The difference between the brightest and darkest settings that the screen can display
• Higher contrast ratios are typically better
• There is no standard measurement across brands
• Connections
• What type of cables can be used to connect to the monitor

The optical drive is used to read and write files to CD, DVD and Blu-Ray discs. Many newer laptops forgo including an optical drive to maximize the portability and minimize the weight. External USB optical drives are commonly used for computers that do not have one installed.

Major Specifications

• Write ability
• Some optical drives will only be able to read disks and thus will not be able to write.
• Compatibility
• Not all optical drives will be able to read/write CD, DVD, and Blu-Ray disks. Check which disks each optical drive is compatible with.

A storage device is like the file cabinet of the computer (long-term storage for data like documents and photos). Hard Disk Drives (HDD) or more commonly referred to hard drives are the 'old-fashioned' type of storage. Because the technology is well established the advantage of HDDs is that they are cheap and can come in large storage options. The other type of storage are Solid State Drives (SSD). SSDs are faster, more durable, and generally more reliable but since the technology is relatively new it is pricier and is not available in large storage quantities.

Major Specifications

• Drive Capacity
• The capacity of a storage device is how much data it can store.
• The measure of data that can be stored on a storage device is most commonly measured in Gigabytes (GB) or Terabytes (TB), 1TB being approximately 1,000GB.
• Drive Speed
• HDDs have a spinning disk and the drive speed is the measure of how fast the disk is spinning in rotations per minute or RPMs
• Since SSDs are just compressed chips and have no moving parts, this measurement is not applicable to SSDs
• Common drive speeds are anywhere between 5,400 RPM and 15,000 RPM.
• Read/Write Speed
• This is the speed in which your computer can read and write data to and from your storage device. This is most commonly measured in Megabytes per second or MB/s (1GB is approximately equal to 1,000MB)
• HDDs have read/write speeds of anywhere between 50 MB/s and 190MB/s
• SSDs can range from 100MB/s to 500MB/s

Hard Disk Drive (HDD):

Solid State Drive (SSD):

Input/Output (referred to as IO and I/O) is what interfaces in between devices.

Major Specifications

• Function
• Data - many I/O ports and cables are designed for data transfer (ie USB is designed for moving files between devices)
• Display - this is for outputting display on another screen (ie HDMI is used to send display information to another screen)
• Power - the I/O type designed to carry power to and from devices (ie an increasing number of computers are using USB-C chargers to power computers)
• Connection Type
• Many connection types exist for I/O these are just some of the most common
• USB-A (most commonly referred to as just USB) is the most common connection type for I/O
• USB-C (the newer type of USB) is capable of doing data, display, and power. USB-C is relatively new but is expected to be the primary I/O type in the near future. Thunderbolt 3.0 also uses a USB-C sized connection and can more efficiently carry data, display, and power.
• 3.5mm Headphone Jack is the dominate I/O type for outputting music
• HDMI does video and audio output and is the main display I/O type
• Mini-DisplayPort does video and audio output, in addition Thunderbolt 1.0 & 2.0, which have a Mini-DisplayPort sized connector, can carry data.
• Ethernet is the I/O type to use when connecting to a network
• SDXC Card Reader is for reading SD cards
• Power Adapter the exact connection type varies by manufacturer but is used to deliver power to the computer

Additional Resources

• Cable Connection Guide