Compare and contrast desktop and laptop components

Most of the functions that a desktop can perform can also be performed by a laptop. However, these two kinds of computers are built very differently and the parts are not interchangeable. As an example, a plane and a helicopter can each travel to the same destination, but they cannot be repaired with the same spare parts. This is also true for laptops and desktops. Few components can be shared between desktops and laptops.  

Desktop components tend to be standardized. They usually meet universal form factors. Desktops made by different manufacturers can often use the same components. A DVD/CD-RW drive is an example of a desktop component that has a standard form factor.  

Laptop components are much more specialized than desktop components. This difference is because laptop manufacturers focus on refining laptop components to make them more efficient and compact. As a result, manufacturers design laptop components to follow their own specific form factors. Laptop components are proprietary. As a result, you may not be able to use components made by one laptop manufacturer to repair a laptop made by another manufacturer.  

NOTE: Technicians may have to obtain certification for each laptop manufacturer that they support.  

After completing this section, you will meet these objectives:

• Compare and contrast desktop and laptop motherboards.
• Compare and contrast desktop and laptop processors.
• Compare and contrast desktop and laptop power management.
• Compare and contrast desktop and laptop expansion capabilities.

Compare and contrast desktop and laptop motherboards

Desktop motherboards have standard form factors. The standard size and shape allow motherboards from different manufacturers to be interchangeable.

Laptop motherboards vary by manufacturer and are proprietary. When you repair a laptop, it is strongly recommended that you obtain a replacement motherboard from the manufacturer of the laptop. Figure 1 shows a desktop motherboard and a laptop motherboard.

(images are displayed on the next occasion)

Laptop motherboards and desktop motherboards are designed differently. Components designed for a laptop generally cannot be used in a desktop.

Compare and contrast desktop and laptop processors

The central processing unit (CPU), or processor, is the brain of the computer. The CPU interprets and processes instructions that are used to manipulate data.

Laptop processors are designed to use less power and create less heat than desktop processors. As a result, laptop processors do not require cooling devices that are as large as those found in desktops. Laptop processors also use CPU throttling to modify the clock speed as needed to reduce power consumption and heat. This results in a slight decrease in performance. It also increases the lifespan of some components. These specially designed processors allow laptops to operate for a longer period of time when using a battery power source.

NOTE: Technicians should refer to the laptop manual for processors that can be used as replacement processors and for processor replacement instructions.

Compare and contrast desktop and laptop power management

Power management controls the flow of electricity to the components of a computer.

Desktops are usually set up in a location where they remain plugged into a power source. Desktop power management distributes electricity from the source to the components of the desktop. There is also a small battery in the desktop that provides electricity to maintain the internal clock and BIOS settings when the desktop is powered off.

Laptops are small and portable. This portability feature is achieved by combining the small size and weight of a laptop with the ability to operate from a battery. When the laptop is plugged in, laptop power management sends electricity from the AC power source to the laptop components. The laptop power management also recharges the battery. When the laptop is unplugged, laptop power management takes electricity from the battery and sends it to the laptop components.  

There are two methods of power management:

·         Advanced Power Management (APM)

·         Advanced Configuration and Power Interface (ACPI)

APM is an earlier version of power management. With APM, the BIOS was used to control the settings for power management.  

ACPI has replaced APM. ACPI offers additional power management features. With ACPI, the operating system controls power management.  

Compare and contrast desktop and laptop expansion capabilities

Expansion capabilities add functionality to a computer. Many expansion devices can be used with both laptops and desktops:

·         External drives

·         Modems

·         Network cards

·         Wireless adapters

·         Printers

·         Other peripherals

Expansion devices are attached to laptops and desktops differently. A desktop attaches these devices with serial, parallel, USB, and FireWire ports. A laptop attaches these devices with the same ports and PC Cards.

The standardized use of USB and FireWire ports makes it possible to connect many types of external components to laptops, docking stations, port replicators, and desktops. The USB and FireWire standards make it possible to connect and remove external components without the need to power off the system. USB and FireWire ports are used to connect a range of external components:

·         Printers

·         Scanners

·         Floppy disk drives

·         Mice

·         Cameras

·         Keyboards

·         Hard drives

·         Flash drives

·         Optical drives

·         MP3 players

Laptops and desktops have similar expansion capabilities. It is the difference in form factor between the computers that determines which type of expansion device is used. Desktops have internal bays that support 5.25″ and 3.5″ drives. Additionally, there is space to install other permanent expansion drives. Laptops have limited space; therefore, the expansion bays on laptops are designed to allow different types of drives to fit into the same bay. Drives are hot-swappable and are inserted or removed as needed.

Laptops use the PC Card slot to add functionality. The PC Card slot uses an open standard interface to connect to peripheral devices using the CardBus standard. Here are some examples of devices that connect using PC Cards:

·         Memory

·         Modems

·         Hard drives

·         Network cards

PC Cards follow the PCMCIA standard. They come in three types: Type I, Type II, and Type III. Each type of PC Card is different in size and can attach to different devices. A newer type of PC Card is called the PC ExpressCard. The PC ExpressCard comes in 34mm and 54mm widths