How To Build A PC: From Component Selection To Installation

Step 2: Select Your CPU

Processor selection can be summed up in three words: performance, power, and price. Our Best Gaming CPUs For The Money column includes general performance and pricing data that applies to both gamers and non-gamers alike, and additional performance data is found in our CPU Performance Charts. It’s also important to know that when our gaming gurus recommend an overclockable “unlocked” processor, the non-overclockable version may offer the same standard-speed performance for less money. Overclocking is a group of techniques designed to push a part’s frequency beyond its designed operational parameters (voltage, heat, etc).

Those same CPU charts show idle and peak power draw, and specific power draw under various types of applications can be garnered through thorough reading of our CPU reviews.

Today, enough software relies on multi-core processing that AMD and Intel have all but eliminated single-core products from their product portfolios. Single-threaded workloads are still fairly common at the consumer level, and technologies like Turbo Boost (from Intel) and Turbo Core (from AMD) are designed to accelerate CPUs when they encounter those lighter tasks. As you read through our processor reviews, the Apple iTunes workload we run is a good example of a single-threaded test.

It’s certainly nice to know that modern operating systems can spread the load of multiple tasks over several cores, and that software developers can break certain tasks into jobs that multi-core processors can handle concurrently. But you're still wondering how many cores you need. If some are good, are more better? 

Not necessarily. Software isn't optimized to run across an infinite number of execution cores, and the more resources you duplicate on-die, the more complex your processor becomes, drawing more power. As with all things, there's a balance to strike, depending on what you use your PC for. If you're browsing the Web, responding to email, and writing in Word, most modern dual-core CPUs will feel plenty-lively. But once you start transcoding videos for your tablet or editing pictures taken on your DSLR, it gets a lot easier to overwhelm mainstream hardware.

Game developers have been trying to take advantage of multi-core processing for several years, yet we’ve rarely experienced a significant performance increase from having more than four cores. That’s probably why the largest manufacturer of desktop CPUs, Intel, focuses its gaming-oriented message primarily on four-core processors with the latest advancements in per-core and per-clock productivity.

Unable to match its chief rival in per-clock performance, AMD first countered by releasing processors with more cores for less money. The extra resources can come in useful in heavily-threaded tasks, but a big bump in clock frequency was the only thing that could keep AMD's older technology competitive in gaming circles. That came in late 2013 with two factory-overclocked models.

Power consumption is a major concern in environments where acoustics have to be kept in check. Typically, as you increase power, cooling requirements go up too. And that often means faster-spinning fans, which make more noise. The latest generation of low-energy Intel and AMD processors makes great strides in performance per watt used. Intel also offers even more miserly S-series variations of its Core i7 and Core i5 CPUs that can reduce heat inside high-performance machines.

Once you have a general concept of your own performance and power needs, the above-referred CPU Performance Charts, reviews, and Buyers Guide should help you narrow down a list of specific models you’d like to try. Of course, if you need a little extra guidance, check out Tom's Hardware's CPU forums, where you can ask questions and get answers.