The short version
- P-cores (performance cores) are big, fast cores built for peak speed. Your game's main thread wants one.
- E-cores (efficient cores) are much smaller. Intel fits about four in the space of one P-core, so they add lots of multi-thread muscle for little power.
- LP E-cores (low-power E-cores) sit away from the main cores so the chip can handle video, browsing and idle time with the big cores switched off.
- A "24-core" chip isn't 24 equal cores. Check the split, because a game cares far more about the P-cores than the total.
First, what is a core?
A core is a complete processor inside the CPU chip. It's the part that actually runs instructions. Every program, from your game to your browser, is a long list of small steps: add these two numbers, fetch that value from memory, compare it with this one, jump to a different step if they match. A core works through that list very fast. A modern core can do billions of steps every second.
Each core has its own maths units, its own logic for working out which instruction comes next, and its own small, very fast cache memory for the data it's using right now. That's why one core can run a task on its own, start to finish.
The list of steps a core is working through is called a thread. One core runs one thread at a time. Some cores can juggle two by switching between them whenever one is waiting on memory, which Intel calls Hyper-Threading.
Before 2005, most home PCs had a single core, so everything took turns on it. Now a CPU packs many cores onto one chip, and each can work on something different at once. One core runs the game's main logic, another builds the next frame's draw commands, a third loads textures, and others keep Discord and Windows running in the background. More cores means more things happening in parallel. That only helps, though, if the software splits its work up, and games are hard to split evenly.
That brings us to the newer twist. The cores in one chip no longer have to be identical.
Why a CPU has different cores at all
For years, every core in a desktop CPU was the same. Adding more of them made chips faster at video rendering and compiling, but each big core costs a lot of silicon and power. Most of the time your PC isn't using all of them anyway.
Intel's answer, in Alder Lake (12th gen) in 2021, was to mix two designs. Phones had been doing this for a decade, with Arm's "big.LITTLE" approach. Intel brought it to PCs: a few large cores for speed, plus a block of small ones for everything else.
Image: Zerocade
P-cores: the fast ones
P-cores are the wide, high-clocked cores that chase single-thread speed. They're the ones that hit the headline boost clocks. Recent designs are Lion Cove (Core Ultra 200 desktop chips and Lunar Lake) and Cougar Cove (Panther Lake).
Games care about them most. A game usually has one main thread doing the heavy work each frame, and if that thread waits, your frame rate drops no matter how many other cores sit idle. That's why single-thread scores matter so much for gaming.
E-cores: the small ones that add up
E-cores are simpler and slower per core, but tiny. When it introduced them, Intel said a cluster of four E-cores takes up about the same area as one P-core. So instead of adding two more P-cores, Intel can add eight E-cores.
They take background jobs, like Discord, your browser, a stream encoder or a game's loading and shader work, and they pile on for heavy multi-thread tasks. Current designs are Skymont and Darkmont.
LP E-cores: the ones that save your battery
Meteor Lake, launched at the end of 2023, added a third type. Two LP E-cores sat on a separate low-power section of the chip, so a laptop could play a video or idle with the main cores fully powered down. Lunar Lake in 2024 took it further: four P-cores, four LP E-cores and no regular E-cores at all.
Today's Panther Lake chips can have all three types, up to 16 cores in total. And the leaked Intel Moon Lake goes to the other extreme, with just four LP E-cores and nothing else, for very cheap laptops.
Image: Zerocade
Who decides which core runs what?
That's the job of Thread Director, hardware inside Intel's hybrid chips that watches what each thread is doing and passes hints to the operating system. Windows 11 uses those hints to put demanding work on P-cores and light work on E-cores. Windows 10 supports these chips but lacks the full Thread Director support, so Windows 11 is the better pairing.
It wasn't smooth at the start. When Alder Lake launched, some older games using Denuvo DRM refused to run because the E-cores looked like a different PC. Patches fixed most of them. Today you'll still see advice to switch E-cores off in the BIOS for gaming. On paper that rarely helps on a modern chip, since the background tasks then crowd onto your P-cores instead.
Reading a spec sheet
The total core count hides a lot. Here's how some well-known chips split up:
Image: Zerocade
A Core i9-14900K and a Core Ultra 9 285K are both "24 cores", but only eight of those are P-cores. One more thing: on Core Ultra 200 desktop chips, Intel dropped Hyper-Threading, so 24 cores now means 24 threads rather than 32. AMD takes a different route with "compact" cores like Zen 5c, which run the same design as its full cores in less space at lower clocks.
Next time you compare CPUs for gaming, look at the P-core count and the boost clock first. The E-cores are the tiebreaker for streaming and multitasking, and the LP E-cores matter mainly when you're on battery.
