CPU – Processor

This is likely the area most people will feel comfortable with prior to building a computer; so this section will provide more in-depth knowledge including descriptions of a CPUs function and importance in a build, differences between AMD and Intel [Jan 2016 accurate] and finally, an introduction and overview to overclocking.

Function and Importance 

The processor performs “the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions” – in more simple terms, it is the brain of the computer. [Source]

It is therefore a crucial part of all computers and for everyday tasks such as using Office programs, browsing the web etc… this is where spending more money will often give the most noticeable performance.

A processor’s speed, clock frequency, is measured in Hertz and for CPUs today this is usually given in Gigahertz, GHz, which is one billion Hz.


There is more to a CPUs performance than simply the clock speed, the number of cores is also important and whether Hyper-Threading is present [Source]. Hyper threading is a feature allowing one core to appear as two units (logical processors) and was introduced over a decade ago; but through implementing this technology, computational parallelisation is improved – it increases how much “stuff” is processed in a given time and leads on to my next point. The IPC (instructions per clock) value is probably the easiest thing to use to differentiate CPUs, and we’ll explore this is AMD Vs Intel, but this is a measure of how many operations can be done in a set time – so the higher the better.

Fun fact: There are processors with over 60 cores! The Intel Coprocessor 7120D is designed for servers however, not for general use [Source].

If like me, you’re after high performance in order to play games well, then you’re going to want to ensure you dedicate a nice portion of your budget to the CPU. How much? That’s up to you. However, I’d advise this be one of your top priorities – improvement wise, if the trend continues, you could stick with the same processor for four years, or more, without needing a replacement. If you’re short on cash and doing a budget build, my advice is to always ensure you’ve got strong CPU power behind you and leave the graphics card out if possible, until the next pay day.

AMD Vs Intel

This is a topic which harbours many ill feelings in the gaming community, I’ve seen hundreds of arguments started on forums even on matters unrelated to CPUs regarding which is best.

In my experience, in a brief summary – if you’re on a budget, AMD and if not, Intel. It’s a shame that is a view shared by so many people, but it is the state of the CPU market right now and hopefully will change soon with the release of the new generation of AMD’s.

As of 01/2016, generally:


  • Fewer cores, but stronger
  • Higher IPC
  • Cooler
  • Use less power


  • More cores, but weaker
  • Lower IPC
  • Hotter (not by much)
  • Use more power

There are some great deals on AMD CPUs to be found and if you’re on a budget this can be a good idea – however, from the benchmarks I’ve seen and price-to-performance values, anything above an FX8350 will not be worth it [Source]. Exceptions are plentiful, many enthusiasts will use AMD in their rigs getting exactly the performance they want and in gaming, as will be discussed in the GPU section – graphics cards matter more.

Ultimately, set yourself a budget for the CPU from your overall – plug the maximum value in pcpartpicker and browse, as always – read reviews! Once you’ve got a processor in mind, whichever brand, compare it to it’s closest rival on the other side – google for example “FX 8350 vs ….” and the moment you put ‘vs’ in, plenty of results will pop up showing benchmarks people have ran between similarly priced CPUs. Once you’re aware of what performance you can get in that price range, make your decision based on that.


Overclocking [Source]

To overclock a CPU means to increase its core frequency beyond the stock value, which often requires additional voltage and almost certainly a third party CPU cooler (not the one included in the box). The reason you will need a higher quality cooling system to combat the increased temperatures encountered through upping the voltage.

The maximum safe temperatures will vary, of course this isn’t something that manufacturers openly advise doing and you can only find out roughly what overclock your CPU is capable of through research. This is a confusing subject for those unfamiliar with the technology, as processor chips are silicon based circuits – the manufacturing process involved cannot ensure uniformity in quality and performance above a set value, hence this is the reason Intel CPUs are clocked at around 3.5Ghz – the stock value. It also means based you’re never assured of what overclock is possible, you could buy 10 identical CPUs cooled by the same unit and all could achieve different clocks. Research online and you’ll see those unfortunate souls stuck with a somewhat disappointing +0.5Ghz to their stock, whereas the average (Intel) with a sufficient cooler probably lies around 4.5Ghz, 1Ghz more than stock.

Fun fact: the highest overclock ever recorded is nearly 9Ghz! [Source]

Overclocking will increase the power drawn by the CPU, which you will need to account for if you plan on doing it, so make sure you get a sufficient power supply.

I will include another section on overclocking in a blog post at a later date, detailing exactly how you do it and the tests required to ensure stability.


My Experience

I have the i5 6600K in my own computer build (09/2015)[Source] and put the i5 4690K in my younger brother’s PC (12/2015)[Source].

The 4690K right now is a great contender for “best CPU” if you could generalise something so incredibly, it’s well priced, performs extremely well and runs cool.

I put the Skylake 6600K in my own since I had a much larger budget to work with and, for reasons we’ll discuss in the Motherboard section, it’s sometimes worth spending a bit more to ensure you have the platform to upgrade upon in the future.