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Understanding Computer Performance Fundamentals



Ever notice how fast your computer is when you first got it? And how over time, and after so many installs of applications, it got slower? And now you are contemplating purchasing a new computer...DON'T!

If you read this article, you might just save yourself several hundreds of dollars. Read on to find out.

The objective of this article is to help you understand the fundamentals behind computer performance. After reading this article, you will know the following:

  • The primary computer resources responsible for performance
  • Activities or situations that can cause computer performance issues
  • What you can do to improve computer performance

The Big Four


Computers have four key components that contribute to its job performance. When your computer slows down, one of these four components has become a bottleneck. What does this mean? It means that the component has reached or is reaching its capacity.

The four computer components involved are:

  1. CPU (processor)
  2. Disk (hard disk drive)
  3. Network (ethernet or Wi-Fi card)
  4. Memory (RAM or Random Access Memory)


The CPU or processor is the computing power or brains of your computer. The CPU might be running at some clock speed like 3 GHz, and now-a-days you may find that it has 2, 4, or even 6 cores (computing engine). Typically the higher the processor speed and the more cores it has, the higher processing capacity it has (i.e. it can accomplish more per clock cycle).


Disk (a.k.a. secondary memory) is where data are stored. This is where you store your documents, your pictures, videos, movies, etc. The operating system also resides on the disk drive. The disk drives buffer size, number of spindles, cylinders, and its RPM (rotations per minute) determine its speed. RPMs for disk drives range from 3000 to around 15000. Also note that data throughput measured on disk drives is in units of MB/s (mega bytes per second). Note: the fastest disk drive is still orders of magnitude slower than memory. That is why when the computer starts using virtual memory (which goes into the disk drive), your computer starts getting sluggish.


Network refers to your computer's network interface. If you are wired into your home's network, it would be called the Ethernet adapter. However, if you are using a wireless access point, then you are using a wireless network Interface. Most people just call this WiFi interface. The speed of the network is measured in Mbps (or mega bits per second). Most Ethernet adapters run at 100 Mbps, and even 1000 Mbps. Wireless speeds vary. It can be anywhere up to 300Mbps. If your wireless signal is poor, it can do down as low as 1Mbps.


Memory is also known as RAM (random access memory). When a program runs, your computer loads it in memory. If there isn't enough room, it will load only parts of the program it needs. As the program runs, it will read from the disk and load the program to memory as it needs. Computers extend its memory to virtual memory--located on the disk. When a computer needs more memory than it has, it has to depend on virtual memory.

memory - hard faults per sec

memory - hard faults per sec

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Resource Impacts to Computer Performance

Unless your computer is infected with some form of malware, its resources will impact performance as follows:


Programs and services use up memory. As you load more programs or install more memory resident services, memory is used up. As more memory is used up, your computer begins using virtual memory to handle peak memory demands.

As memory demands exceed the physical memory limitations of the computer, the computer uses more virtual memory, and in the process start to get sluggish. When this happens, look at the activity LED indicator of your disk; it is probably flashing continuously.

Watch out for new program or device installations. They install programs that run in the background. Over time, these little programs can eat up your memory, causing your computer to slow down.


If memory isn't being MAXed out, the disk drive can be a computer performance bottleneck if you simply performed disk intensive operations like disk copies or disk writes. Try running a program, like MS Word, while you perform a foreground backup of your movie collection. You will notice sluggishness in MS Word because it is now competing for disk access with your backup.

Aside from this, fragmentation can add to the sluggishness. Files on a computer's hard disk drive are stored in storage units called blocks. A computer can extract data faster if the file is stored in a contiguous sequence of blocks. Over time, files change and thus get scattered in the hard disk over non-contiguous blocks. When this happens, the file gets fragmented. When more and more files get fragmented, the computer will take longer and longer to read files. This is why computers perform better when you first get them. Then over time, it starts to perform poorly as data and program files get fragmented on the hard disk drive.


Much like the disk, the network interface can be a bottleneck if it is busy transmitting or receiving data continuously. It can also be a bottleneck if the network it is connected to is busy; this means that your computer might be waiting for some response to a server over the network, and will simply wait with an hourglass until that response comes back. This is one aspect of the network resource that makes it unique to the computer system. In other words, it can be a bottleneck as a result of external circumstances.

In general, the network isn't the first resource to bottleneck, unless you determine that the wireless signal is poor and you end up with a 1Mbps connection.


When your computer is busy computing, the CPU utilization will go up. If ever the CPU utilization goes to 100%, you will find that the computer becomes totally useless. In general, you will not or should not see the CPU utilization stay at 100%. There should only be some occasions you see this, and some of them might be when you are generating a movie file from a video project, or you are doing a full virus scan of your computer, or something similar where computation is required.

You will also find that there are poorly written programs that can put your computer into a loop, pushing the CPU utilization to 100% and locking up your computer in the process.

Improving Computer Performance

Before you buy a new computer, you may consider upgrading or replacing key computer resources first. What can you do?

Upgrade Your Memory

If you presently have only 1GB of RAM and you still have one free memory slot, why not buy another 1GB of RAM? Or better yet, get 4GB or more RAM! Memory is always the first resource to bottleneck. You can never have enough of it. Now-a-days, memory is cheap. With more memory, you can have more windows open and run more programs.

If you have no money to spend, try getting rid of those pesky startup programs that take up some of your memory. Do this by running MSCONFIG and clicking the Startup tab. There you will see a list of programs that run at start up. If you recognize any that you don't need; just uncheck therm.

Replace your Root Drive or Add a Faster Disk

Every year I'm finding that the price of disk drives are dropping while its capacity is increasing. Also, relatively new are the new breed of solid state drives. It has no moving parts, and has a faster performance than traditional mechanical disk drives; the only down side is price. They are more expensive than the traditional drives; but if you have a few bucks to spare, go for it.

If you are totally broke, try disk defragmentation first. Defragmenting your disk drive will pack the files in a contiguous manner so as to help with disk access speed.

Upgrade Your Network Connection

Most network interfaces run at 100Mbps, and most wireless connections can achieve 54Mbps. The actual bottleneck in today's home network is the speed of your Internet connection; which might range anywhere from 512Kbps to 2Mbps Because of tough competition for Internet service out there, you may be able to upgrade to a faster service than what you have now. Check the competitors, you may be able to get faster speeds at practically the same monthly rates.

Upgrade your CPU

In most brand name computers, you cannot change change the CPU to a different type; all you can do is replace it with the same exact one. However, if you build your own, there may be an option to replace it or add another CPU (if you have a multi-socket CPU provision.

Another option is to overclock the CPU. Do this only if you are willing to risk burning out your CPU or you are really sure of what you are doing. By overclocking your CPU you are basically increasing the clock input to your CPU, allowing your computer more cycles per second.


Computer performance simply depends on the following not becoming bottlenecks:

  • CPU,
  • memory,
  • disk,
  • and network.

Each of these can become a bottleneck, depending on your demands.

Regardless, there are many things you can do short of buying a new computer to deal with poor computer performance.

Good Luck! And let me know if you have any questions.


J Forlanda (author) from US of A on August 06, 2012:

Thanks. I'm glad it is of use to you.

flashmakeit from usa on August 05, 2012:

Your article is helping me! I will return to read more.

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