When a computer is slow, it needs to be diagnosed. There is even a theory called General Troubleshooting Theory that helps make the diagnostics faster and more precise. That technique is mainly used by Apple.
Just because we have only one or two computers at home, a simple technique can be used by testing every laptop or PC component.
Just before we start the test, we need to say that operating systems need adequate memory in order to function properly. If there is not enough memory, an operating system will use a hard disk to store part of the necessary memory on it.
The other factor that affects computer speed is hardware faults. We have seen a lot of cases when, for example, various hard disk faults will slow the computer down. To diagnose the hard drive, there is a good program called GSmartControl. This program is fast and also displays S.M.A.R.T. data, what is most important is it displays the type of error that happened inside the hard disk. For example, it displays how many read errors occurred during the lifetime of the hard drive. If there are a lot of errors, then we know that the disk surface has a bad sector.
Figure 1: Slow computer performance caused by a faulty hard disk
Maybe it is repeated and repeated again, but first of all, the hardware must be tested. Another good tool to test the hard disk is to use HDTune. A simple version is free and this version is enough to test the hard drive adequately. The main difference of GSmartControl is that it gives a visual indication of the fault it displays and shows where the bad sector is. On the GSmartControl, the information is displayed in numbers. And, with GSmartControl, the decision about the health of the hard disk can be made faster. In realty, it takes just a couple of minutes to check the numbers and make a decision. With HDTune, we would need to test the hard drive surface, and this can take up to one hour.
Figure 2: A bad sector on a disk can slow the computer down or make it unstable.
As mentioned in other articles on this site, viruses also are within the top ten factors that can slow the computer down. Usually, one of the purposes of a virus is to replicate itself. This is done by making copies of itself and trying to spread through all possible communication, including email, LAN network, open operating system ports, flash drives, etc. When it copies itself and infects other files, most of the processor recourses are used for this purpose. Also, viruses are made using programming language, and they are sometimes buggy, as the creators don't care about proper testing and debugging.
Slow desktop PCs are probably easier to diagnose as all components are easily accessible.
What can cause a desktop PC or a laptop to slow down:
Faulty hard drive
Faulty power supply
Faulty capacitors on the motherboard
Faulty north bridge or south bridge BGA soldering
Faulty memory RAM
Faulty graphics card
Faulty broken USB ports
nVidia graphics, BGA soldering on the motherboard or on the graphics card
Figure 3: An example of a faulty power supply
Figure 4: Faulty capacitors on the motherboard
Figure 5: Defective RAM cells
The age is also important for computers and laptop health. If it is five years old and it has a faulty motherboard, then it is probably worth it to replace the motherboard as the components on the motherboard will cost a substantial amount of money.
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