We are often asked to investigate why a computer is running slowly and what can be done to make it faster. Diagnosing the reason a computer is running slowly requires checking all of these potential causes, since the symptom alone is not enough to differentiate or isolate the cause. This list is not comprehensive; there are some other unusual and rare causes that will make a computer run more slowly.
1. Insufficient RAM to run all programs in memory without swapping to the hard drive.
Solution: compare commit charge to physical RAM and add RAM memory.
2. Bad hard drive; disk errors creating delays.
Solution: test and repair or replace the hard drive.
3. Low performance CPU.
Solution: replace a Celeron CPU with a Pentium CPU for improved performance.
4. Overheating due to failed fan or excessive dust blocking heat sink.
Solution: clean accumulated dust using compressed air.
5. Bad motherboard due to failed capacitors that are cracked, leaking or bulging.
Solution: replace the motherboard or the system unit.
6. Memory leak; software bug causing a program to use increasing amounts of RAM until restarted.
Solution: upgrade the software causing the excessive memory usage or restart more frequently.
7. Wrong video driver making the display run slowly.
Solution: upgrade the video driver software in Windows device manager.
8. Low performance wireless connection due to 11mbps wireless B or distant antenna with a weak signal.
Solution: upgrade wireless router or access point.
9. Too many add-ons or excessive toolbars in Internet Explorer or Windows startup.
Solution: use MSconfig to remove startup programs, use add-on manager in IE7 and later to remove unused add-ons and toolbars.
10. Viruses and spyware stealing memory and processor performance.
Solution: use Malwarebytes and other scanning tools to identify and remove extraneous software.
11. Low performance hard drive with 2mb cache or 5400-rpm spindle motor:
Solution: replace hard drive with faster 8mb cache and 7200-rpm spindle motor or SSD drive.
Contrary to popular opinion, the number of programs installed on a computer does not affect the performance. Removing or un-installing programs will generally have no effect on performance. Freeing up disk space by deleting programs and other files will not improve performance. Defragmenting a hard drive can improve performance but has a minimal effect on increasing performance.
Instead, its the number of programs that are currently running that determine how much RAM is being used, and it’s this RAM usage that determines performance. The Windows tray icons next to the clock are a good indication of the currently running programs that will reduce RAM and performance.