What is a Computer?

If you’re looking for a new computer you may have found that you now have more questions after your initial enquiries than you had before you started to look. This is a pretty normal experience when we are faced with technical terms and jargon that only makes sense to people in the sales industry and computer technicians. So in order to help you make a better buying decision and to prevent you killing some young computer salesperson we have laid out the essential guide to understanding the difference between Gigahertz and Gigabytes.

The first step to understand what you are buying when you hand over your cash for that box of silicon chips and wires is to realise what it is and why it was invented. Before we had computers the work they are now used for was done in offices where filing cabinets were beginning to become industries in themselves. The computer was brought in as a tool to help organise and streamline these systems of files and hope that they would eventually replace paper in the workplace. This did not entirely happen as hoped but the structure and original need for the computer was established and is now integrated into every office in the world.

This might seem like it is starting to seem irrelevant but when you think about how the parts work together you can start to see the logic to how it all works. If we think of a computer like an office it starts to come together. Let’s think of the components of an office:

Filing cabinet: This central storage point for documents and files in a structured and searchable system is an essential part of any office. In the computer world this has been replaced by the Hard Drive. This new storage device can hold literally millions of times more information than a filing cabinet. The storage capacity is measured in Gigabytes, you’ll often see it listed as 160GB or 500GB or in some cases 1TB which is 1000GB. To put that into context; if you were to type the entire Encyclopaedia Britannica into a computer you would take up the equivalent of 1GB.

Office Desk: The working space of the office. This is where the work physically happens. This has been replaced in the computer world by RAM. So the 2 or 4 GB of RAM you see listed on the specifications of a computer refers to the available working space on your computer. Again think of the GB beside the number in this situation using the Encyclopaedia Britannica concept – if all you use the computer for is documentation then you don’t need 4GB or 4,000 times the workspace required to open it. In saying this a picture quite literally speaks a thousand words minimum so opening large picture or video files will take up significantly more of this workspace.

Secretary: The one that actually does the work around here some might say and in this case they would be perfectly correct. Emulated but never replaced the secretary inside the box with the blinking lights is now known as the processor. When you click your mouse on “My Documents” and it opens a window showing you the contents it is the Processor that has gone to your Hard Drive (filing cabinet), found the file you requested and opened it on your RAM (desk) for you to see. This happens very quickly as the processor does things at an incredible speed which is represented in Gigahertz or GHz on the specifications you’ll see listed. 2.6GHz for example is 2.6 million processes per second which I will explain further on.

Advertising Department: Not every office has one of these but the ones that do always seem to look better. This is down to the focus of a dedicated marketing manager and department where the work can happen unhindered by the regular office duties. This function in a computer is taken by the Graphic Card. With a dedicated Graphic processor and Graphics RAM the display is taken care of separately to the regular computing that the Main Processor is designed to take care of. A specialist for a special task! Not all computers have these but the ones that do can handle advanced graphics tasks such as Gaming and 3D Graphics rendering a whole lot better than one without it.

Now you might be have been wondering what is GHz? Without getting too technical the differences between the various processors that list the same clock speed, but have different price tags, have a significant difference in actual speed. Here is a brief explanation of the term:

As I said earlier GHz is the equivalent of one Million processes per second. I say equivalent because it’s a little more complicated than that and goes beyond the scope of this buying guide. In simple terms, imagine each one of these millions of processes or electrical signals is a car on a motorway. This motorway will only allow one car at a time per lane which means that each car has to wait until the one before it got to the end of the motorway so the lane is completely empty from start to finish. This is how the signals are sent from a processor to the relevant part of the computer only some of the cars can carry more than one passenger and the motor ways have different speed limits hence the difference in actual speed and workload that gets completed in a given time. Now you might say build more lanes and you’d be perfectly right as that is what terms such as Multi thread (which adds lanes) and Multi core (which adds entire new motorways) achieve in different ways and increase speed and performance.

I hope you now have at least an understanding of what you are buying so you don’t get bogged down in jargon and technical terms that made no sense up until now.

The range of Processors that you will on the market find have varying speeds and very strange names I imagine are chosen by what appears to be star trek fans. Often the speeds can double as the range progresses due to advancements in technology but here is a list ranging from the fastest to the slowest:

(Note: Laptops often carry a mobile version of these processors which are significantly slower due to power limitations in relation to battery life and fitting a cooling fan into such a thin frame)

  • Intel Core i7 
  • AMD Phenom 2 X6 
  • Intel Core 2 Quad 
  • AMD Phenom 2 X4 
  • Intel Core i5 
  • AMD Athlon 2 X4 
  • Intel Core i3 
  • Intel Core 2 Duo 
  • AMD Athlon 64 X2 
  • Intel Pentium 4 

So, happy hunting and don’t be afraid to ask the sales advisor in the store to explain what something means if you don’t understand it. They get asked all the time so they are well used to explaining how it works.

Ronan Clarke

Harvey Norman

Airside Retail Park,

Swords, Co Dublin


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