What is Quad Core?

A quad-core processor is a chip with four independent units called cores that read and execute central processing unit (CPU) instructions such as add, move data, and branch.

Within the chip, each core operates in conjunction with other circuits such as cache, memory management, and input/output (I/O) ports. The individual cores in a quad-core processor can run multiple instructions at the same time, increasing the overall speed for programs compatible with parallel processing. Manufacturers typically integrate the cores onto a single semiconductor wafer, or onto multiple semiconductor wafers within a single IC (integrated circuit) package.

Although it's tempting to suppose that a quad-core processor would operate twice as fast as a dual-core processor and four times as fast as a single-core processor, things don't work out that simply. Results vary depending on the habits of the computer user, the nature of the programs being run, and the compatibility of the processor with other hardware in the system as a whole.

Quad-core and higher multi-core processor configurations have become common for general-purpose computing, not only for PCs but for mobile devices, smartphones, tablets and TV Streaming Devices.

Comparing Dual Core to Quad Core:

Multicore CPUs first appeared on the desktop and laptop PC platforms around 2005. Though Intel currently has the lion's share of different x86/x86-64 multicore processor models, AMD beat Intel to market with its Opteron dual core back in April 2005. The Intel Pentium D dual core followed in May 2005. Quad-core desktop, laptop, and workstation processors followed on in the next few years, followed shortly by the six-core or hexa-core processor, and now the single-core processor is all but a memory. Processors with six cores and beyond are found in high-end systems, with eight-core processors common in servers and hundreds of multi-cores in AMD and Nvidia graphics processors. Now the question is, should you buy a dual- or a quad-core processor for your next desktop or laptop PC?

What It Does
Having a multicore CPU means that the processor can work on more than one problem at a time, or it can work on a large problem more efficiently if the program is built that way. Multitasking is easy to explain: If you're browsing the web, checking email constanly, and calculating the 20,000 cells in your latest spreadsheet all at the same time, having multiple cores means that core 1 can be working on the email, core 2 on the Flash webpage you're viewing, and cores 3 and 4 on the spreadsheet. When you have a single task that needs to be done right away, multiple cores can help you by breaking the task into smaller chunks, working on each chunk in parallel, and thus you'll get your work done quicker. An example of this is the 3D rendering of a still image. Most modern rendering programs can break the task into blocks, then parcel those blocks to each core as needed, and then the final image is put together at the end.

More Cores or Faster Clock Speed?
On the whole, a system with a faster dual-core will feel faster in day-to-day work, but the quad core will reward you when you multitask or the more esoteric/scientific your work. This is of course, a generality, but it generally fits. For example: The 3.1GHz Intel Core i3-2100 (dual-core) in the Gateway ZX6961-UB20P got a very good 2,639 point score at PCMark7 (a test of day-to-day use), but only a 2.99 point score at CineBench R11.5 (a 3D rendering test). Around the same time we tested a "slower" Intel Core 2.7GHz Core i5-2500S (quad-core) in a HP Compaq 8200 Elite USDT which got a much lower 2,190 score on PCMark7, but a much higher 4.45 point score on CineBench. The extra cache and cores in the i5-2500S helped the HP get a much higher score on the CineBench R11.5 test, where such enhancements benefit performance. In day-to-day tasks, both will seem similar, or at worse the HP will seem slower than the Gateway at an earlier stage in its useful life. We could present you a large table of comparison scores going back several years, but that would add even more variables to the mix and bore most of you to tears.

So, What Then?
When purchasing a new computer, we invariably tell folks to buy as much processor that they can buy in their budget. You can (almost) always upgrade your memory or get speedier storage in the future when your computer starts to "feel slow" (and they all do after a while). More memory and speedy storage helps any PC feel faster because you spend less time waiting for stuff to happen. Upgrading to a faster processor isn't an option for most mortals, unless they are familiar with the pain of unhooking heat sinks and spreading thermal paste. Looking at benchmarks in PC reviews still counts for something: A system that is the fastest in its class when you buy it will continue to feel faster longer than a system that is merely adequate when you buy it. You want a quad-core processor if you're the type that likes to keep 150 browser tabs open while you check your IM, email, Twitter, and Facebook simultaneously, and then want to do photo editing work in Photoshop or play 3D intensive games on top of that. If all you're doing is puttering around the Web and don't expect anything strenuous from your PC aside from an emotional Angry Birds session, a dual-core processor is sufficient.