Whenever you think of buying a computer or going in for an upgrade, the first thing that comes to your mind is – which processor? And if you are one of those people for whom all the technical jargon never seems to make sense, here is a guide to buying the right processor.

1). The ‘core’ problem:

This one of the most commonly asked questions, which processor should I go in for? A dual-core or a quad-core (2 core processor or 4 core processor)? And then there is this widespread misconception that every quad-core processors is faster than every dual-core processor (taking into account the present software architecture).

To understand this, we have to know how a processor truly works.

Even if you are using multiple applications on your computer, your processor can actually supply its processing power to one application at a time. But when you are using your computer, there are lots of processes going on – some you know about, some you don’t. If you are reading this article on your browser and your media player is playing your MP3 – that are two visible processes. But what about the rest of the operating system? What about your internet connection? The sound that is coming out of your speakers? Those are invisible processes for you, but of course they require a processor.

To make this possible, a processor switches between different processes continuously. It gives a particular application some of its processing time and then switches on to the next one. This is made possible by the scheduler of the operating system. Easy enough to understand I guess? Well, continue reading.

Now, most applications these days are programmed only for a single processor. That means, there may exist four cores on your processor but the application/ software you are using has no idea that they exist. This is because they are not programmed to work on multi-core processors.

Unless the software you use has been specifically programmed to work on multi – core processors, there won’t be the speed difference you expect to see. In other words, you won’t be making use of the four cores the way you thought you would.

Windows and Linux can make use of multi – core processors by allocating different cores to different processes. This however is not equivalent to an application running on different cores.

To understand this even more clearly, take the next example.

You have two processes A & B and two cores. A & B have not been programmed for use on multi – core systems. This is how your OS allocates the CPU to them:

Core 1 -> A
Core 2 -> B

Now consider a process A, for example a video encoding application that has been optimized for multi – core system. It has two threads (consider a thread as a subdivision of the process), A1 and A2. A1 + A2 make up the process A.

Core 1 -> A1
Core 2 -> A2

So what is now being done is the process A is being run simultaneously on two cores instead of one. This is called parallelism and this is the case where the benefits of multi – core systems are there.

Put simply, most applications today that you use – from your browser to your MP3 player have not been optimized for multi – core systems. Though this is slowly changing, however we are not that stage that every application would make use of multi – core processors. For such applications, the multiple cores don’t exist.

However if you are used to running multiple processes simultaneously – like playing a game while your chat client records the logs, then go in for a multi – core system. In that case, the benefits are obvious.

If the above doesn’t matter to you, the thing you should be worried about is the clock speed of the processor – the one that is measured in GHz. The frequency. That’s right – if you are using a 3.0 GHz dual – core processor and your friend has a 2.4 GHz quad – core processor, chances are your computer would be much faster than his. And like I said, support for dual – core processors has started to roll out (some 3D games support two cores now), but for quad – core support there is a lot of time.

So, don’t go in for a single core processor obviously, but if you are choosing between a dual – core processor and a quad – core one, and the dual core has a higher clock rate, go in for that. Be technical, don’t follow the hype!

2) The Cache Memory

The cache memory is the memory that can be accessed fastest by the CPU. It is located on the CPU itself and when the CPU needs to read / write data to the memory, the first place it looks for is the cache. If the data is not there, then it goes over to the RAM which takes time. Put simply, the cache is the fastest memory available on your computer. However it is very expensive and so its size is limited to a few MB only.

A processor with a higher cache is faster than a processor which has a lower cache. When buying a processor, look out for the cache specification. It is clearly mentioned on the processor box (or the website).

3) The FSB (Front-Side Bus)

The FSB or the front-side bus is the bus (bus is a subsystem that transfers data between computer components inside a computer) that carries data between the CPU and the RAM and the AGP port. The faster the FSB speed, the more quickly the CPU can communicate data to and from it. I won’t go into much details, but when buying a processor, look for the one with the higher bus speed, which is measured in MHz.

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So when buying a processor, there are essentially four things you should look out for:

Go in for a dual – core minimum and a quad – core or higher if you can. However, don’t compromise the three specifications below just for the sake of more cores!

Clock speed - the frequency – measured in GHz . The higher, the better.

Cache - measured in MB – The higher, the better.

FSB - measured in MHz – The higher, the better

Feel free to comment and discuss the article. I will try to answer any queries you might be having.

Useful resources:

How many cores do you need?

What should I look out for when buying a processor?