Intel's "efficiency cores" are a borderline scam

Since several generations now, most Intel CPUs have shipped with two types of cores: "performance" and "efficiency" cores.

The "performance cores" are your normal full-on full-power full-speed cores, as normal. The "efficiency cores", however, are slower but less power-consuming cores.

That's not a big secret, Intel is completely open about it, and pretty much every tech-savvy PC user knows that. However, most PC users greatly underestimate how inefficient those "efficiency" cores actually are.

The "efficiency cores" allow Intel to proclaim impressive numbers. For example, an Intel Core i9-13900K processor has 24 cores, which support hyperthreading, and thus have 48 threads!

24 cores (48 threads) sounds quite impressive!

Problem is, only 8 of those cores are actual performance cores. The remaining 16 are "efficiency" cores.

And "efficiency" cores are very, very inefficient. In actual reality you are getting only 8 actual real full-on full-power cores. The rest are just 16 significantly slower cores. And the 24 extra "threads" do not add all that much computing power either (hyperthreading does improve processing power somewhat, depending on the application, but not all that much.)

If we compare raw computing power, you are getting, perhaps, 10 actual cores worth of it. 12 at the very most. The computing power of those extra 2-4 "pseudocores" is divided into 16 "efficiency" cores and the 24 hyperthreaded virtual cores.

In other words, in terms of raw performance you are not getting 24 cores. At most maybe 12. (And from those, 4 are harder for programs to use because they are divided into multiple smaller cores and virtual cores.)

One problem with this is that, for example, video games might use more than those 8 true cores for heavy-duty calculation, and it may cause slow framerates and dropped frames. If even one computing-intensive task ends up in one of those slower cores, the rest need to wait for it.

Windows/Linux will try to prioritize the performance cores for computing-heavy threads, but if eg. a game uses more than 8, some of them will end up on the performance cores, potentially causing performance issues.

So, ironically, it would be better to buy a processor with eg. 12 actual full-on cores than this "24-core" CPU that has only 8 real ones.

Intel is capitalizing on "24 cores, 48 threads" sounding impressive, but it's very deceptive.