What to Look for When Buying a Desktop Computer

Looking for simplified desktop computer buying guide. Read the article till end to know more about what to look for when buying a desktop computers.

But before that I want you to know about simplified explanation of how the computer works. It will help you to choose better desktop computer

Many of you leave me messages asking you to describe how a computer works.

So, as usual, I will try to answer you simply, describe to you the role of the main elements of a computer and we will look at how a computer works.


Before I wrote this article, I thought, but why are I so often asked to describe how a computer works?

There must be tons of articles that explain that?

Indeed, there are many, but I confess that by reading them I understand better. Indeed, most really comes into detail by talking about cores, PCI slots or even binary codes so that for the uninitiated, this is incomprehensible.

I’m not saying I’m going to do better, but I’m going to try to do differently by focusing on the essentials and avoiding as much as possible all too technical terms.

General presentation.

The easiest way to understand is always a small drawing:

Here are the essential components of a computer (and still screen, keyboard and mouse could be removed).

Computer operation

How does a computer work?

I told you I was going to do it! (I think that I will have to write a part 2 of this article by developing a little more).

Before looking at the functioning, let us now look at the role of each:

  • The hard drive is a hardware that will allow to save the data. We can compare it to a notebook or school notebook where we would come to write and read the information that we would like to keep. We will come back. (The hard disk is sometimes referred to as mass memory.) The data written to the hard disk remains even when the computer is turned off.
  • The RAM is the memory (not permanent) of the computer, we could compare it to our memory (yes, we do not record everything for life!). This memory disappears when we turn off the computer.
  • And finally, the processor also called CPU is the brain. It is he who controls the whole and it is he who will calculate, and treat the different incoming or outgoing information.

These components are all inside the computer and rarely accessible. They are all plugged into a large electronic card that makes the size of the computer: this card is called “motherboard”.

Here is an example of a motherboard:

On the motherboard above, there is no processor or ram. But simply insert them on the supports provided for this purpose.

  • Keyboard and mouse, I will not linger but know that this is called input devices. (I give the explanation on the notion of device just a little lower). The information always goes in the peripheral direction to the processor.
  • The screen is an output device. The information always goes in the processor to device direction. (For example, the printer is also an output device). (Be careful, the new touch screens are also input devices because you give information to the computer by tapping on the screen).

A device is as its name indicates something that is around. (Think of the ring road around the big cities). In computer science one could say hardware connected to the computer. The keyboard and the screen are around the heart of the computer (although often they are delivered with or even included in on the laptops).

Role of a computer.

Before we talk about functioning, let’s talk about the role and what we expect. If you bought a computer, you expect something:

  • Surfing the Internet,
  • To play,
  • Watch videos,
  • Working (entering text, making calculations, …)
  • Save and sort your photos,

In fact, every time you do something: you have to use software.

What is software?

A software (or program) is a file that contains a sequence of operations (or instructions) that your computer must perform.

Let’s take an example in everyday life and compare our software to a work in a factory. You are a worker in a factory that produces parts, and your manager describes you your position which consists of:

  • Take part A in the box,
  • Drilling a hole in room A,
  • Take part B in another box,
  • Screw the part A onto the part B,
  • If the two pieces fit correctly then
    • Assemble the two parts A and B on the conveyor belt.
  • If not
    • Throw the 2 pieces in the trash
  • End of work.

All your work is described on the instructions manual. This manual is written in a language you understand (its better!)

You can compare the software to this instruction manual, everything is described there. As you can see, this is a sequence of operations and the work can take different directions by answering the different questions (in the example: “if the 2 pieces fit correctly then …”).

As for you, the software is written in a language understandable by the one who will carry out the operations. And in this case, the software is written in a language that the computer understands. (This is a binary code, a sequence of 0 and 1).

But developers (those who make software) do not write software with 0 and 1. They write in a development language, and a translator tool (compiler) will convert this language into 0 and 1)

And for your culture, to learn a new language, developers often start with a small program called “hello world”

Here is the list of instructions this little program:

  • Show “hello world” on the screen,
  • Close the program.

It may seem ridiculous, but depending on languages ​​and especially when you start, it is not always easy to do.

 Hardware and software.

And here, without realizing it, we have just evoked 2 very used concepts:


Hardware is all that concerns the hardware part of the computer. (Example: motherboard, processor, memory (RAM), hard disk, etc.)

Hard means hard, ware means merchandise, and finally hardware could be translated by hardware .


And therefore in contrast, everything that is not material is software (software).

Soft can be translated as soft (as opposed to hardware hard).

How the computer works

When you press the power button, the whole system starts (but as I said I was going to make it simple, I will not talk about it here, but in a complementary article).

When the computer starts up, it starts by launching special software called OS (for example Windows, Linux or MacOS.) I do not go into details, but if you want to know what an OS, I advise you: What is an OS? ).

Without this OS, you cannot use the computer and the computer would only be a machine that would not help much. It is the OS that will interpret your commands and show you the results. (This is an overlay between the hardware and you).

Modern OSs usually display a home screen (called desktop) containing all of your icons. These icons will allow you to launch the software by clicking on it.

Here’s how it works when you run software: let’s look at it step by step. (Attention, always for a better understanding, the steps have been deliberately simplified)

  1. You click (or double click) on the icon.
  2. The computer will then search the hard disk to which software points this icon.
  3. It will read the software from the hard drive because it is recorded on it.
  4. All that will be read will be loaded into the RAM.
  5. From the RAM, the processor will run the instruction software after instruction.
  6. Once you close the program, it will be erased from the RAM.
  7. But of course, it remains present on the hard drive for a next use.

Detailed presentation of each of the elements

RAM (Random Access Memory)

RAM is a (volatile) memory. It is a chip card. These cards are called barrettes. The advantage of memory is that reading and writing information is done very quickly.

The disadvantage is that this memory disappears as soon as the computer is switched off. Moreover, since this RAM has a certain cost, if we wanted to store all the information, it would be very expensive.

Here is a RAM array:

it is not possible to store everything in RAM (cost, and data loss when the computer is turned off), it was necessary to invite mass and permanent data storage systems. At the beginning of computing, this was done on perforated cards, then on magnetic tapes and finally appeared the hard disks.

Hard disk

As we just saw above, the hard drive stores information. The advantage of the hard disk is that you can store a lot of information and that this information remains saved even if you turn off the computer. You can save your software, photos, music, …

The cost of storage is significantly cheaper than with RAM. On the other hand, reading and writing are much slower than with RAM.


However, a hard disk is composed of an electronic part and a mechanical part (disk, motor, reading head, …): all this can break down and then all or part of what is recorded is lost ! Believe me this happens quite often.

I cannot advise you to make a copy of the important files that you want to keep on another medium (2nd hard drive, DVD, external hard drive, cloud, …).

The new SSD hard drives are composed exclusively of electronic chips (much like RAM, except that the information does not fade when the computer is switched off). They also have the advantage of being very fast.

If you want to know more about the operation of a hard drive, I advise you to read: How does a hard drive work?


And finally, the processor. It is he who executes the instructions.

A processor is composed of transistors. These are small chips that will let the current pass or not according to the value at the input and the requested operation: much like a switch, this state can be 1 or 0 (on or off, On or Off).

All these operations must be started at a very precise rhythm: this rhythm is clocked by a clock. The faster the clock, the faster the processor can process the second. At each clock pulse, the transistors will assume a state 0 or 1, which will make it possible to make calculations.

Remember the example of the procedure sheet above, and imagine that the processor performs an action at each pulse of the clock.

This timing is expressed in GHz. (Giga Hertz, Hertz being a frequency unit). We can talk about a 4GHz processor. Either 4,000,000,000 cycles of operations per second!

All processors are not equal, and you could think of doing a good deal by taking a processor that goes faster than another. But speed is not enough. To go faster some processors have multiple cores and built-in cache memory, but then I get lost: I had said I would do simple. What I just wanted to say is that 2 processors at 4GHz will not necessarily have the same performance!

I hope that this explanation (willfully) very simple will allow you to better understand the basic functioning of a computer.

It is not excluded, that I return there to create a second part a little more detailed.

Here are the some of the examples of best desktop computers for you

1. Lenovo 19 Inch Desktop Set

What to Look for When Buying a Desktop Computer

Save: ₹ 64,000.00 (71%)

  • Intel i3 4th Gen
  • 8 GB RAM
  • 500 GB HDD
  • 19″ Wide Monitor
  • 5 Years Warranty

2. Gandiva® CI51ST Desktop


Save: ₹31,115.00 (61%)

  • Core i5 1st Gen CPU
  • 4GB DDR3 RAM
  • 500GB HDD
  • 2GB Graphics/WiFi
  • Free MS Office
  • Free Antivirus

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