What Do “Dual Core” and “Quad Core” Mean?

When you are purchasing a new laptop or building a computer, the processor is the most important decision. But there’s a lot of jargon, especially the cores. Do you need a dual core, a quad core, a hexa core, an octo core…

Let’s cut the jargon and understand what it all really means.

Dual Core vs. Quad Core, Explained

Here’s everything you need to know:

• There is always only one processor chip. That chip can have one, two, four, six, or eight cores.
• Currently, an 18-core processor is the best you can get in consumer PCs.
• Each “core” is the part of the chip that does the processing work. Essentially, each core is a central processing unit (CPU).

This article deals with dual core vs. quad core processors for computers, not for smartphones. We have a separate post on understanding smartphone cores.

How Speed Is Affected by Dual- and Quad-Core CPUs

You might think more cores will make your processor faster overall, but that’s not always the case. It’s a little more complicated than that.

More cores are faster only if a program can split its tasks between the cores. Not all programs are developed to split tasks between cores. More on this later.

The clock speed of each core also is a crucial factor in speed, as is the architecture. A newer dual core CPU with a higher clock speed will often outperform an older quad core CPU with a lower clock speed.

Power Consumption

More cores also lead to higher power consumption by the processor. When the processor is switched on, it supplies power to all the cores, not just one at a time.

Chip makers have been trying to reduce power consumption and make processors more energy efficient. But as a general rule of thumb, a quad core processor will draw more power from your laptop (and thus make it run out of battery faster).

More Cores Equal More Heat

More factors than the core affect the heat generated by a processor. But again, as a general rule, more cores leads to more heat.

Due to this additional heat, manufacturers need to add better heat sinks or other cooling solutions.

Are Quad Core CPUs More Expensive Than Dual Core?

More cores isn’t always a higher price. Like we said earlier, clock speed, architecture versions, and other considerations come into play.

But if all other factors are the same, then more cores will fetch a higher price.

It’s All About the Software

Here’s the dirty little secret that chip manufacturers don’t want you to know. It’s not about how many cores you are running, it’s about what software you are running on them.

Programs have to be specifically developed to take advantage of multiple processors. Such “multi-threaded software” isn’t as common as you might think.

Importantly, even if it’s a multi-threaded program, it’s also about what it is used for. For example, the Google Chrome web browser supports multiple processes, as does video editing software Adobe Premier Pro.

Adobe Premier Pro instructs different cores to work on different aspects of your edit. Considering the many layers involved in video editing, this makes sense, as each core can work on a separate task.

Similarly, Google Chrome instructs different cores to work on different tabs. But herein lies the problem. Once you open a web page in a tab, it is usually static after that. There is no further processing work needed; the rest of the work is about storing the page in the RAM. Which means even though the core can be used for a background tab, there is no need for it.

This Google Chrome example is an illustration of how even multi-threaded software might not give you much of a real-world performance boost.

Double the Cores Is Not Double the Speed

So let’s say you have the right software and all your other hardware is the same. Would a quad core processor then be twice as fast as a dual core processor? Nope.

Increasing cores does not address the software problem of scaling. Scaling to cores is the theoretical ability of any software to assign the right tasks to the right cores, so each core is computing at its optimal speed. That’s not what happens in reality. In reality, tasks are split sequentially (which most multi-threaded software does) or randomly.

For example, let’s say you have a quad-core processor (Core1, Core2, Core3, Core4). You need to accomplish three tasks (T1, T2, T3) to finish an action, and you have five actions (A1, A2, A3, A4, A5) like this.

Here’s how the software will divide tasks:

• Core1 = A1T1
• Core2 = A1T2
• Core3 = A1T3
• Core4 = A2T1

The software is not smart though. If A1T3 is the hardest and longest task, the software have should split A1T3 between Core3 and Core4. But now, even after Core1 and Core2 finish their tasks, they have to wait for the slower Core3’s task to complete the action.

All of this is a roundabout way of saying that software, as it stands today, isn’t optimized to take full advantage of multiple cores. And doubling the cores does not equal doubling the speeds.

Where Do More Cores Really Help?

Now that you know what cores do and their restrictions in boosting performance, you must be asking yourself, “Do I need more cores?” Well, it depends on what you plan to do with them.

Dual Core and Quad Core in Gaming

If you fancy yourself to be a gamer, then get more cores on a gaming PC. The vast majority of new AAA titles (i.e. popular games from big studios) support multi-threaded architecture. Video games are still largely dependent on the graphics card to look good, but a multi-core processor helps too.

Editing Videos or Audio

For any professional who works with video or audio programs, more cores will be beneficial. Most of the popular audio and video editing tools take advantage of multi-threaded processing.

Photoshop and Design

If you’re a designer, then a higher clock speed and more processor cache will increase speeds better than more cores. Even the most popular design software, Adobe Photoshop, largely supports single threaded or lightly threaded processes. Multiple cores isn’t going to be a significant boost with this.

Should You Get More Cores?

Overall, a quad core processor is going to perform faster than a dual core processor for general computing. Each program you open will work on its own core, so if the tasks are shared, the speeds are better. If you use a lot of programs simultaneously, switch between them often, and assigning them their own tasks, then get a processor with more cores.

Just know this: overall system performance is one area where far too many factors come into play. Don’t expect a magical boost by changing one component like the processor. Choose wisely and buy the right processor for your needs.

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