How to Build a PC - CPU Selection

In the last edition of this ongoing blog series we introduced this project and went over budget concerns for planning your build, you can find it here.

Selecting Components: CPU

When building a system, it is a good idea to start by choosing which CPU you want to use and then building around it.

Intel versus AMD

The debate rages on today, and probably will continue for years to come. This is actually a great thing since it forces both companies to innovate and find new ways to add features and increase performance in order to stay competitive with each other. There are typically certain price ranges you can expect any generation of CPU to fall within.

• With the new "Skylake" 6^th Generation Intel Core processor family you can expect to pay anywhere from $129 to $1069.
• The latest generation AMD FX AM3+ socket CPUs range from $99.99 to $299.99.

The sweet spot for most builders is going to be in the $150 – $300 price range. This is usually where you can get the best "bang for your buck." Most CPUs which cost over ~$300 are going to cost a lot more per % of increased performance, which means that you might be better off spending that extra money towards upgrading something else in your build, such as your graphics card, a mechanical keyboard, or a larger monitor. Most CPUs which cost under ~$150 will often have less than optimal thermal and over-clocking characteristics, and may not be as good in the long run; especially if you think you might get your feet wet with overclocking.

When it comes to CPUs there are a few ways you can compare their performance characteristics on paper, the one everyone is likely familiar with is the CPU frequency, or clock speed. CPU frequency is actually stated in two values with modern CPU, In "Max Base Frequency" and "Max Turbo Frequency" (in GHz). In addition to the speed of the CPU, you should also compare the number of cores, thermal design power (TDP) and Cache (L1, L2, and L3). On paper, you won’t always get the most accurate picture of performance, so you will also need to look at some real world benchmarks in order to get a tangible idea of how any two CPUs compare. There are hundreds, if not thousands of reviewer sites that will present this information to you. Below is a sample of a comparison of current CPUs that I grabbed from Tom's Hardware which is an excellent resource for system builders and hardware enthusiasts.

• Max Base Frequency: This is the clock speed of your CPU when it is operating under a typical load.
• Max "Turbo" Frequency: Both AMD and Intel CPUs have a built in performance mechanism which will increase the CPU frequency when it is under heavy load.
• Cores: How many CPU cores the chip has. More cores means you have more multi-tasking power, but as time goes on and software gets smarter about utilizing multiple cores more efficiently, increased numbers of cores on a chip become even more attractive.
• L1, L2 and L3 Cache: CPU Cache (the "L" stands for "Level") is the amount of data that can be stored temporarily on the CPU, while it’s waiting to be processed. Common CPU instructions will be stored within the various CPU cache levels to greatly reduce any delay in processing data. This is similar to how memory works, however cache memory is integrated directly into modern CPUs and is capable of responding to and delivering data much faster than the systems RAM (Random Access Memory).
• TDP (Thermal Design Power): This is the amount of power the CPU is expected to use when it is operating within a typical real world environment. This is not a maximum operating temp, but more of an indication of how much power the CPU will use and how hot it will get. Keep in mind that any overclocking of the CPU will increase CPU heat, and will likely require an aftermarket CPU cooler.

In the next post, we will cover the things you should know when picking out your motherboard.