Intel processors explained: What is Core i3, i5, i7, Ultra and Pentium?

The most common brand of processor in laptops you can buy in the UK is Intel. However, Intel's myriad of marketing names for its various processors can make comparisons extremely tricky. 

In this guide, we’ll explain what different Intel processor models mean and what sort of user they’re best suited for. Then, for those who want all the details, we’ll explain some of the techie differences between the various Intel chips you can buy so you can ensure you get the best processor for your needs and budget.

Whatever your budget, our lab tests reveal which models are worth your money and which aren't. See our expert pick of the best laptops

The basics: Which Intel processor is best and what should I choose?

The following advice is for recent Intel processors less than four years old. It’s general advice, too; read the section afterwards for more information on how to differentiate between processors of the same type. 

Atom 

Don’t bother. These aged chips have no place in modern laptops, and aren't up to the demands of modern software and websites. The most recent Atom used in laptops is from 2016 and it was hardly fast back then.

Celeron, Pentium or ‘Intel Processor’ 

Up until recently, there were separate brands for Celeron and Pentium processors. Intel has now bundled both of them up into a brand called Intel Processor followed by a model name that often starts with N. In any case, these chips are fine for doing basic tasks one at a time and are typically paired with 4GB of Ram. 

Intel Core i3 or Core 3 

Intel has rebranded its Core i3 (and i5 and i7) line-up, ditching the iconic 'i' it's used for 16 years. It doesn’t change our advice, though. These chips are good for light work, and can easily handle a few tasks at once and a few web browser tabs. They’re typically paired with 4GB of 8GB of Ram. Starting from £300.

Intel Core i5 or Core 5 

Typically paired with 8GB (and sometimes 16GB) of Ram, these processors are the best way to get yourself a computer that’s nippy enough for multitasking with lots of programs, documents or web browser tabs open at the same time. Also great for editing photos. Starting from £450.

Intel Core i7 or Core 7 

Similar to the i5 or 5 above, these are great for multitasking and photo editing, and are often excellent for editing videos as well. Laptop makers often charge a heavy premium for upgrading to an i7, but for most people it isn’t necessary. Starting from £700.

Intel Core i9 

An even faster range of processors with more cores and faster speeds. These are reserved for very expensive laptops. Starting from £1,500.

Intel Core Ultra 5 and 7 

This is a new brand for Intel, and it marks laptops as being faster and more power efficient than the lesser brands. They also have the ability to completely turn off parts of themselves to save power. Ultra processors have dedicated built-in chips specifically designed to handle AI-related tasks, although their use is limited to a small number of specialist apps. Starting from £1,000.

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Latest Intel laptop reviews

Below, you'll find the latest laptops we've tested that have various types of Intel processor. A Which? membership will unlock the reviews and reveal whether they're Best Buys – join today.

Intel Core i5 laptop review

Intel Core i3 laptop review

Intel Pentium laptop review

Intel Core Ultra 7 laptop review

(Recommendations checked September 2024.)

Intel processors: key terms you need to know

When looking at a processor, there are two main figures you’ll see time and time again. 

1. Clock speed

This is measured in gigahertz (GHz) and tells you how many operations a processor can do each second. The higher the number, the faster the computer (when comparing processors of around the same age).

You’ll notice a higher clock speed when opening programs, files and exporting photos.

2. Number of cores

Typically, laptop and desktop chips have two or four cores (known as dual-core and quad-core). Some newer models have six or even eight. The more cores, the better because it allows your computer to run multiple tasks at the same time without slowing down. 

You’ll appreciate more cores if you often have lots of programs running or open lots of web browser tabs. 

However, comparing the number of cores between different types of Intel processor (such as comparing an Intel Atom with an Intel Core i5) won't tell you much as the cores themselves are completely different. For example, four Atom cores are much less powerful than two i5 cores.

What are performance cores and efficiency cores?

Sometimes you’ll see laptop manufacturers touting a lot of cores – for example, a laptop that might have had four cores last year now has 14 or more. While it’s technically accurate to say that there are 14 cores in this hypothetical example, it’s split between four ‘performance’ cores and 10 ‘efficiency’ cores (P and E cores for short).

P cores do the brunt of the work on your computer and are the cores that use the most power. However, when the processor recognises that a task doesn’t need full power, it can command the E cores to work on it instead, saving power. In some cases, all 14 cores can work together on big tasks like converting a video file. 

The most important factor for overall performance is the number of P cores, but a larger number of E cores is no bad thing.

See our pick of the best budget laptops

What do the numbers and letters at the end of Intel Core i processors mean?

The make-up of an Intel Core i chip model name can be broken up into five parts, each part giving you a little more information about the processor in your computer.

The first part is the easiest: the branding (such as Celeron, Core Ultra, Core 5, etc) are the processor's brand and tells you broadly where it fits into the range.

Within each range, there are three more elements to consider.

Part one: generational number

The first digit (or two digits) after the dash tells you which generation the processor is from.

As of 2024, they all start with the number 1 after Intel reset its Intel Core branding. Before that, we got all the way up to the 14th generation, so all model numbers started with 14.

This is useful to know, as it can not only help you know the age of a laptop if you're buying used or refurbished, but it also lets you easily compare between two models. 

The newer the processor, the better performance you'll get for the money. But if two models of laptop have processors perhaps only one generation apart (12th gen versus 13th gen, for example), the difference between them will be pretty small. So if the 12th-gen model is substantially cheaper, it could well be a better buy.

What are the generations of Intel processor?

Below, you can see which year each generation of Intel Core processor was launched, plus the codename you'll sometimes see them referred to as.

See our guide to buying used or refurbished laptops.

Part two: position in range

After the generation number, you get two or three digits that tell you roughly where in the hierarchy the processor sits. 

If you compared the two numbers in two processors, for example Core i5-1145G7 and 1140G7, you could glean that the 1145G7 was more powerful. However, Intel doesn't recommend you use these numbers for comparison as the 'bigger is better' mentality may not always hold true as there are other technical differences that aren't apparent from these numbers. It's good to know anyway, though.

Part three: suffix

The suffix (trailing letters or letter and number) gives you more information about where the processor sits in the range. The suffix in our example is Core i5-1145G7, but there are other variations, including the i5-11300H and the 11600, which has no suffix at all. 

Below is a list of the common suffixes you'll find:

• U suffix: Ultra-low power, primarily found in laptops. This wasn't used much for laptops between the 10th and 14th generations but has returned on Intel Core Ultra processors to differentiate them from 'H' processors (below).
• H suffix: This suffix has returned for Intel Core Ultra processors. It distinguishes higher-power Ultra processors with more performance cores (for example the Ultra 7 155H has six performance cores where the 155U has two).
  
• G and a number at the end Processors from the 10th-generation onwards (models starting with, 10, 11, 12, 13 or 14) often end with a G and a number – for example, G1 or G7. The higher the number on the end, the better the built-in graphics chip on the processor will be. The product listing should provide more detail as to what sort of performance you can expect.
• No suffix This is a standard desktop processor, generally with four cores and a high clock speed for excellent everyday performance, and the ability to edit videos and photos at high speed.
• T suffix Found in smaller desktops and all-in-one PCs. These chips are functionally the same as those without a suffix and have the same number of cores, but with a slower clock speed.
• K suffix The highest-performance processor you’ll find in a computer you can buy on the high street. Similar to a chip with no suffix, but generally with a higher clock speed. These chips can be ‘overclocked’ by those with technical knowledge.
• HQ suffix Generally found in powerful laptops and normally come with four cores. Perfect for video and photo editing, but sacrifices battery life and portability.
• Y in the middle (older chips only) These are the lowest-power chips you can find. They aren’t really suitable for photo or video editing, but will be fine for lighter tasks. The advantage of choosing one of these is very good performance for lighter tasks coupled with a longer battery life. Laptops that use this chip tend to have fanless designs, meaning they’re totally silent and very thin.

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