What is the difference between P-cores and E-cores on an Intel processor

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The world of processors is changing.
Not only do we now have a lot of CPU cores in our laptops and desktops, but we now have a mix of core types, which are P-cores and E-cores.

What is the difference between P-cores and E-cores on an Intel processor

CPU design, symmetrical and asymmetrical

Each CPU core in a typical multi-core CPU is identical.
They all use the same amount of electricity and have the same performance rating.
The difficulty is that while your CPU is idle or doing simple activities, you can’t drop below a certain power usage threshold without shutting it down completely.

When it comes to devices that get their power from the wall, it’s not a big deal, but when you’re running on a battery, every watt counts.

Smartphones quickly adopted a strategy where some power-hungry cores provided peak performance while many efficient cores drew less power, but were good enough to run background system activities or simple programs like email, social networking, or web surfing.

When you launch a video game or in short bursts when the core software requires more power to complete a task, the high-performance cores are automatically activated before reverting to the energy-efficient cores.

Asymmetric computer design

Although the concept of combining different types of CPU cores in a single box is not new, it is uncommon in popular PCs.
At least that’s how it was until Intel’s 12th generation Alder Lake processors.
These are Intel’s first mainstream processors to include a mix of cores.

E-cores (Efficiency) and P-cores (Performance) are found in every 12th-generation Intel CPU model.
The relative amounts of these two types of cores can vary, but the entire Alder Lake CPU chip, found in the i9 CPU models, includes eight P-cores and eight E-cores.
For P- and E-cores, the i7 and i5 models have an 8/4 and 6/4 architecture, respectively.

Advantages of E- and P-cores

This hybrid architectural method in the CPU has several advantages.
Most everyday tasks don’t strain performance, so laptop users will benefit the most.
You’ll have a cooler, quieter computer with longer battery life if all you need is the power of your E-cores.

Those E-cores are still crucial when your laptop is plugged into power or if you’re using a desktop computer.
Suppose you are playing a video game that requires all the power of your CPU.
The game can use all of your performance cores, while your E-cores handle background operations and programs like Slack, Skype, and more.

Intensive programs developed for hybrid CPUs may in the future generate threads that are assigned to both types of cores depending on their requirements.
E-cores are easier to make and cheaper, so using them to supplement and free up high-performance cores is a good idea.

The Alder Lake CPU’s P- and E-cores are, at least, built so that they don’t interfere with each other and can perform their functions independently.

Unfortunately, there are some problems with this fundamental change in the x86 CPU design.


Since combining different CPUs is a new concept for x86 CPUs, there are certainly rough edges to be aware of in the beginning.
Because PC software developers previously had no reason to assume more than one type of CPU in a computer, their software is unaware of the difference between P- and E-cores.
In most cases, this is not a problem because the operating system distributes software threads to the CPU as needed, although some software has been reported to break or behave strangely on these new processor architectures.

Patches for software and legacy solutions at the motherboard level will undoubtedly be plentiful.
Your biggest incompatibility concern may have been resolved by the time you read this.
If you’re running Windows 10 and want to switch to one of these hybrid processors, you should wait or upgrade to Windows 11.
Windows 11 includes a new CPU task scheduler that knows how to distribute work to different types of cores.
While Windows 10 will work, it won’t work as it should, and updates are still being developed to address the issues.

Q and E summary

When it comes time to buy a new CPU, you’ll almost certainly have to decide how many P-cores and E-cores you want.
The best suggestion we can make is to focus first and mainly on the amount of P-nuclei.
To run the most demanding application, you will need cores with adequate performance.
Any additional overhead provided by E-cores is a welcome improvement.

We have not yet encountered two CPUs with the same number of P-cores but different numbers of E-cores.
However, when this happens, it won’t be much of a problem until the next generation of hybrid software becomes widely available.

Even then, it will mostly be a laptop-oriented option.
In short, these are the essential facts you should be aware of:

  • Both high-performance and high-efficiency cores are found in hybrid architecture processors.
    Efficient cores save power while allowing performance cores to focus on the most demanding tasks.
  • Until software upgrades appear, computer applications built for standard CPUs may be confused by hybrid CPUs.
  • To get the most out of these processors, you’ll need the latest version of Windows, at least until previous operating systems are upgraded.

It’s an exciting time for CPU research, and this hybrid chip generation shows that innovative features aren’t limited to ARM-based mobile processors.

Read more on the blog.