Windows Forums member, Bert_H, asked the following question in our suggestion box:

[I’d like] an explanation on i3, i5, i7 Operating Systems, and how they compare with Core 2 and Quad Core CPUs.

Update: Manuel commented asking the following:

It seems core2 duo CPUs have not been included and where they belong. Are core 2 duo CPUs comparable with i3s or even i5s? thanks.

Scroll down or click here for the answer.

If you’re in the market to buy a PC and you’re looking for the best value for money, you’ve likely asked yourself: “what’s the difference between Dual and Quad Core and which should I buy, i5, or i7?”

This guide offers a basic explanation of these processors and will help you determine the best for your needs.

This guide will answer the following questions:

What is a processor?

What is a core?

What is a multi-core processor?

Why do I need multiple cores?

How many cores do i3, i5, and i7’s have?

How Do Core 2 Duo and Core 2 Quad Compare with Core i3, i5, and i7?

What Does the “i” Stand for in i3, i5, and i7?

Do I need an i3, i5, or i7?

What is a Processor?

The Processor or Central Processing Unit (CPU) component of your PC carries out instructions given to it by your Operating System (Windows.) Think of the processor as a brain that receives instructions and messages (i.e. “HOT HOT HOT Burning!!!”) and sends out instructions to other hardware (i.e. “Arm: lift hand” or “mouth: open; vocal chords: scream.”)

What is a Core?

A standard processor has one core (single-core.) Single core processors only process one instruction at a time (they do use pipelines internally, which allow several instructions to be processed together; however, they are still run one at a time.)

What is a Multi-Core Processor?

A multi-core processor is comprised of two or more independent cores, each capable of processing individual instructions. A dual-core processor contains two cores, a quad-core processor contains four cores, and a hexa-core processor contains six cores.

Why do I Need Multiple Cores?

Multiple cores can be used to run two programs side by side and, when an intensive program is running, (AV Scan, Video conversion, CD ripping etc.) you can utilize another core to run your browser to check your email etc.

Multiple cores really shine when you’re using a program that can utilize more than one core (called Parallelization) to improve the program’s efficiency and addressability. Programs such as graphic software, games etc. can run multiple instructions at the same time and deliver faster, smoother results.

If you use CPU-intensive software, multiple cores will likely provide a better computing experience. If you use your PC to check emails and watch the occasional video, you really don’t need a multi-core processor.

How many cores do i3, i5, and i7’s have?

An i3 processor has two cores

An i5 processor has two or four cores (depending on the model you have)

An i7 processor has two, four, or six cores (depending on the model you have)

How Do Core 2 Duo and Core 2 Quad Compare with Core i3, i5, and i7?

Added 2012/01/21:

If you’re looking for a good value PC and have decided on a Core 2 Duo, Core i3, or Core i5 (all best in value for casual computer use), please read on:

Core 2 Duo processors run two threads; i3’s and i5’s run four threads. Core 2 Duo processors are socket 775 (45/65nm); Core i3 and i5 processors are socket 1156 (nm) but only work with DDR3 RAM (Some Core 2 Duo’s work with both DDR2 and DDR3.)

For desktops, I’d stay clear of core 2 duos due to their lack of power and compatibility with the newest PC hardware; for laptops, it all depends on your usage. As laptops aren’t as easy to upgrade, buying dated technology might burn you in the future when you find your Core 2 Duo PC’s motherboard only supports 4GB RAM—for example.

i5’s come with “turbo boost”; however, i3’s overclock very well if that’s your thing. That’s where I’d put my money if you’re considering Core 2 Duo, i3, and i5: the i3 provides the best value for most casual PC users.

While I focused on i3, i5, and Core 2 Duo to answer a reader’s question, the principles apply when comparing i5, i7, and Core 2 Quad. I’d go for the i5 unless you are willing to pay a premium for a little more performance.

What’s the Difference between i3/i5/i7 Generations?

To find out what’s new with the second generation of i3, and i5, and i7 processors, read more about Sandy Bridge here.

To find out what’s new with the third generation of i3, and i5, and i7 processors, read more about Ivy Bridge here.

What Does the “i” Stand for in i3, i5, and i7?

Added 2012/03/03:

I searched around the web and found speculation that the “i” stands for “Intel”; however, there’s no substantiation to that claim. After coming up with no explanation, I sent an email to Intel tech support. Here’s what they had to say (emphasis added):

Hello Rich, Thank you for contact Intel(R) Technical Support. We have received your request. Please be informed that the letter ‘i’ on the model number of the Processor does not stand for any particular detail, technology or feature presented on the product. This is just a marketing brand name decision. For any additional information, please do not hesitate to contact us back. Thank you for your understading (sic). Sincerely, Alvaro A.

Intel Customer Support

The i# processors are just branded that way with no special meaning.

Do I need an i3, i5, or i7?

The reason you’re reading this guide is to find out which type of processor you need. I want to give a simple answer and, if you have more to add, please let us know in the comments. As with all computer hardware, the type of processor you need depends on your needs, for how long you want your computer to stay current, and your budget.

Here’s a very simple breakdown of what you should look to buy depending on your computing needs. All suggestions assume you are buying a pre-built PC (so you don’t have to worry about motherboard and RAM specs and so you don’t have to worry about upgrade compatibility.)

If you:

Browse the internet, check email, and play the occasional flash game (like Farmville): Get a single core netbook or desktop (and don’t spend more than $300 USD — Updated 12/01/21.)

netbook or desktop (and don’t spend more than $300 USD — Updated 12/01/21.) Do word processing, spreadsheets etc., listen to music often, and watch movies, get an i3 processor (or any dual core processor i.e. core 2 duo)

Play the occasional game and are happy with lower resolution and lower quality graphics (my suggestion assumes the graphics processor on the pre-built PC will be well-matched for the processor suggestions), watch HD movies etc., get an i5.

If you do graphic publishing, music creation, programming (and compiling), watch HD movies, or like to play visually appealing games, get a quad core i5 , or i7 .

, or . If you like to have the very best hardware and play the most graphically intense games, get a quad core or hexa corei7 Extreme.

I realise my suggestions are somewhat generic but should point you in the right direction. If you have a specific question, please ask us in the forums where we can help you find the right processor for you.

So… What Computer Should I Purchase?

Added 2012/03/02:

Recently, a number of you have commented asking what computer to buy. As I’m not familiar with all brands, models, and current pricing, I ask that you post your question in Windows Forums where our group of helpful PC geeks will assist in making the choice that’s best for you. Not sure how to use a forum? Start here: How to get great help from Windows Forums.

Last Updated: September 17, 2012

2012/06/23: Added details about i3, i5, i7 processor generations.

2012/09/17: Updated processor recommendations based on pricing and availability. References to hexa core processors.

About Rich Rich is the owner and creator of Windows Guides; he spends his time breaking things on his PC so he can write how-to guides to fix them.

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