Why does a computer become slow?

This is actually a section of the tutorial I received at my work. All the credit goes to the writers of the case. Hope it is useful to others as well.

Why does a computer become slow?

a. Problem with computer specification: Not meeting the minimum requirement to install and operate an OS by its manufacturer

b. Used up (RAM) – One of the most important reasons why computers slow down is that they have too little RAM.Excessive use of RAM by different applications makes the system slow. RAM can be freed by replacing the animated background with a static one and/or by deactivating some enhancements of windows. Even, running new applications or games can slow down the PC.

How can the computer speed be improved without increasing RAM?

Background Programs, Application and Processes and its deactivation – The presence of too many background applications and/or processes as well the use of animated background along with other enhanced mode of windows settings can also slow up a PC. Computer processors have limited multitasking capability. If too many programs are run all at once, the system will have trouble keeping up to the expectation of the user hence, closing some applications before working can smoothen the speed of the computer. All the icons seen in the system tray are background programs that use memory.

To see and remove all running background applications and processes:
Press the Ctrl + Alt + Delete keys at the same time.
Click any program or task except Explorer or Systray,
Click End Task.

This will disable the particular application and/or process for the on-going session only. Please note that it will load again when the computer is booted (started or re-started) again. However, we should be certain about the exact name of the program as the Task Manager will only how the executable files “exe extension” like avp.exe for Kaspersky Internet Security and other “non-executable” or exe files such as system processes.
Virtual Memory Definition – Virtual memory is, as the name suggests, when there is no sufficient RAM and more memory is needed for some games or multimedia programs. The OS or the windows basically to fulfill the requirements of more memory demanding programs or applications makes a new space which can be used in the hard drive like the physical memory so as to fulfill the requirement of the above mentioned programs along with other programs still running in the background. It is just like the RAM but in the hard drive.

If the virtual memory is set too high the PC will obviously slow down because the hard drive is much slower compared to the RAM. It is believed that the RAM is 1000X+ times faster than the hard drive. Excessive virtual memory will take a long time to load the programs. More RAM should be used to let windows utilize a lesser amount of virtual memory or free up some space in the disk.

Hard disk Fragments – Constant installing/uninstalling or deleting of files from the hard drive causes the OS be unable to put the files back to their places in order to save speed. The OS also gives value to the files depending on the number of times used files used more often will be move at the top of the hard disk so that the hard disk can load the program faster than the rest. In the same way the files in the beginning of the drive is accessed much faster than the ones in the end by the windows. Defragmenting of the hard drive with the help of windows defragmentation tool allows to arrange the files and program as per the use and file values. Executing the defragmentation process for the first time may take some time. Defragmentation of the hard disk is done from:

Start menu
Programs
Accessories
System tools
“Disk Defragmenter”.

Unclean Registry – Windows registry is a hierarchical database that stores configuration settings and options on Microsoft Windows operating systems. The Registry contains information that Windows continually references during operation, such as profiles for each user, the applications installed on the computer and the types of documents that each can create, property sheet settings for folders and application icons, what hardware exists on the system, and the ports that are being used.

The Registry replaces most of the text-based .ini files that are used in Windows 3.x and MS-DOS configuration files, such as the Autoexec.bat and Config.sys. Although the Registry is common to several Windows operating systems, there are some differences among them.

Most importantly, viewing, deleting the cache files or uninstalling programs from the system will force the windows registry to store some information related to the application which the windows has to bear even though they are completely useless, and makes a PC slower than the normal.

The problem of unclean registry can be solved and the PC be speeded up by editing the registry manually or by using registry cleaners. But while manually editing, accidental deletion of a legitimate file can cause the entire system to freeze. Thus, genuine and compatible registry cleaning programs should be used to clean the registries.



File Corruption – Improper shut down, frequent power failures etc. causes files to get corrupted. Not only this, file corruption is also caused by the overheating of hard disk drive (HDD).

The corruption of files can be detected and corrected as follows:

Right Click the C drive
Properties
Tools
Click on the check now in the error checking part and answer “Yes” to all the queries and then restart.

If the problem still persists there can be “Bad Block” which is a physical damage in the drive. These bad blocks are also known as “bad sectors” and it means the Hard disk needs to be replaced at the soonest.

If more than one hard disk drive is used there must be space between each of them and it must be kept in mind that cooling options must be applied by different means so that the overheating of the hard disk can be prevented.

Over heating of Central Processing Unit (CPU) can be minimized by cleaning the heat sink and also the fan if possible. Heat sink

Internet connection Problems – Internet related issues, have a lot of variants that make the PC slower than the normal. Some of the common problems related to internet connection are: ISP problem, Line quality problem, Hijacker problem, Firewall, Router, programs running and the windows settings etc.

Partitioning problem – According to the architecture a 250 GB hard drive should be divided into 2 parts and according to the SATA (Serial ATA) architecture a 500 GB hard drive should be partitioned into minimum 2 parts so that the head inside the hard disk drive has to search only half the disk instead of searching the full disk.

Firewall/ICQ/MSN – These are known as the real-time running programs and it is a definite that these programs will slow down the computer’s speed. These software, if run manually instead of allowing to run at the windows startup can boost the computer’s speed. Also the animation, sound, and images in IM software like MSN messenger, yahoo messenger actually need a lot of RAM to handle it.

Windows/Software Auto Update – Auto Update configuration in any program causes the software to run behind the computer and can cause the computer to slow down.

Browsing Multiple websites at the single instance – Browsers need to search for cookies and internet temp file or download it from the site when browsing the webpages which will consume computer system resources. In IE6 even opening a new browser window is a burden for the processor,(in fact IE6 has been considered to be one of the worst IEs so far).

ActiveX and Trojan – Some internet advertisement software and Trojan programs always come along with ActiveX installation, after which these programs will run behind the desktop sneakily. Installing Adware remover or Antispyware can correct these issues.

Internet Pop Up Window – The Internet popup windows are one of the most irritating events and are actually one of the factors to cause the computer slow by wasting the Internet bandwidth.

BT software – Bit Torrent download software engulf the computer’s resources most of the time. It is beyond imagination if more than 10 files are downloaded at the same time. Not only the BT software but also other P2P networking softwares are also responsible in consuming the system resources.

Watching high-resolution video – Don’t think this need to be mentioned; however Media Player Classic normally doesn't take so many resources to watch high-resolution videos. Even the visualization effects available in different media players also slow the computer. It’s better to turn the visualization.

Old or conflicting Windows device drivers – Sometimes there can be two entirely different video drivers on the system and Windows could actually be alternately using both of them this is just an example. This needs a deleting and reloading a driver to correct the problem. Duplicate drivers can and should be deleted.

Hard drive could be too full of data – There should be at least 2MB-3MBs (200,000 -300,000 bytes) of free space to allow for disk file chores. Note that this mostly applies to the C: drive or whatever drive the Window’s cache is on. If C: drive is too full, delete unused programs on the C: drive to make space.

Hardware Problems – Sometimes there can be gradual dying of internal hardware components which often slows down the boot and shut down processes and also causes poor program launches with or without errors or error messages, hence hardware problem is also one of the common causes of a slowing or freezing computer.

Bad Software - Sometimes, software installed in the system might just be badly coded as in the cases of freeware or small shareware programs written by non professionals. These programs tend to make the PC slower consuming system resources.

Poor Security Software that is stealing system resources - It has been found out that a large number of security software programs and suites today demand a large amount of your system resources and memory. This can be one of the reasons to slow the performance of the PC while the security software is constantly scanning and monitoring the computer for threats.

Full Hard Drive and too many Internet temp and windows temp files - When there is less than 10% free space in a hard drive, a dramatic slow down in the performance of the PC can be experienced. This can be corrected by freeing up some space by removing old documents or programs that are no longer needed.
The Internet Explorer temp files folder can become packed and lead to unexpectedly longer launch time for Internet Explorer.

Damaged Operating System - Damaged or corrupt operating system can malfunction and cause the slowing of a PC.

Remnants of uninstalled programs - Uninstalling an application either via the control panel or the application's option leave behind remnants of the uninstalled program which can also slow down the PC because the the Windows will try to figure out what to do with the residue. Not only this the residue of old program stay behind in your system registry as well.
Spyware- Malicious programs that stealthily embed themselves into the Windows Registry and core file system are the most common cause of a slow PC. A lot of malicious websites and applications install themselves (often without a user’s knowledge or consent) into the PC while surfing on the Net. These spyware applications eat up system resources and slow things down.
These spyware programs must be removed as soon as possible to return the PC to top running speed, and before they damage the file system.

Virus – Viruses are closely related to Spyware, viruses can wreak havoc on the system’s performance and severely limit the PC’s ability to do what it can do. Viruses get onto the computer via infected email or instant messages, or get installed via applications or files that are downloaded from file-sharing networks and other non-trusted web sites.
Manual removal of viruses is very difficult and merely an unsuccessful dream therefore, the use of good anti-virus program is a dire need.

Hijacking: The term Hijacking is more often very popular in the world of World Wide Web (www). Hijacking happens without one’s notice it changes the homepage of the internet browser. Hijack can be considered as one of the vulnerabilities of web browsers and it can be a very stubborn problem. Browser hijacks is usually categorized as the Spyware, adware, malware, and other Trojans but it always directly affects the web browser of the computer that it hijacks. Many computer users hardly realize these kinds of programs being secretly installed on their computer. They may also not realize their system or browsers settings being changed. This is also one of the most common reasons that make a PC slow. The following are other reasons that tend to make a PC slower.

A user always sitting in front of the computer running or testing all sorts of programs, surfing the web for all sorts of information, listening to music, watching movies, also playing games above that even consuming food in front of the screen will have his/her computer slow beyond the description. There may be thoughts rising that the hardware is not powerful enough to support the more recent games and the latest applications. This is in this regards as far as the computer is a PIV processor based with at least recommended RAM, we need to keep in mind that there are lots of reasons that are responsible in making a computer slow, hardware don't have anything to do with outdated technology except for gaming purposed which is ruled by the graphics cards.

Modern day programs are designed keeping in mind the high availability of resources and eat away the processing power greatly slowing computer with large amounts of RAM required to store all the data from displaying icons and images to streaming music and playing the appropriate sound effects to creating temporary files on the hard drive for recovery to making sure that the internet connection is up and running all the time. Windows constantly switches data from RAM to hard drive storing the less important data in the latter and recalling it to the former when it becomes important, creating more and more delays and sometimes eventually crashing the system. Absence of firewall, anti-virus and spyware software, in a PC means it is most probably infected with background processes that are working away doing harmful or unimportant stuff further consuming the processor and RAM capabilities.

Thank you @Roshan for this very informative section. @Suvash, yup its like so many differential diagnosis. Usually, when my PC becomes slow I just reformat it. I just think that maybe there is too much junk in it, like too many mucus or there's too much congesion in the nostrils due to dirt and other allergens that stimulates the inflammatory pathway increasing further secretions making the process of breathing really hard and slow (HDD) which then I just flush out with a warm distilled saline water (REFORMAT) which does the trick all the time. And maybe an anti-histamine once a day. (DEFRAG)Sorry for the awful analogy. Thanks again.