What are performance and efficiency cores in Intel's 12th Generation Alder lake CPU Line?

[noorpari76]

I watched Intel's Architecture Day 2021 released in August 2021 (last month at the time of writing this). After watching Intel's video about their new CPU, I was — quite honestly — a bit confused. I guess the new microprocessors are not going to have a 2-to-1 thread to core ratio anymore. Supposedly the i5 will have 10 cores & 16 threads, and the i7's and i9's are similar, I just don't remember exactly what they will be. From what I understand though, the new core-to-thread ratios are the result of specialized cores. If I got this right, some cores are "Efficiency Cores", and they have been named Efficiency Cores and the rest of the cores in the CPU are "Performance Cores", which — to no surprise — have been named Performance Cores.

When new microprocessors are released it can be really hard to know what names, and numbers, are actually based in computer science, and which ones are just a marketing attempt to make the chips look good. In other-words, what I would like to know:

"Is there actually anything to the performance, and efficiency cores, or is it just a marketing ploy? And if the two core are not just a marketing ploy, and having cores for efficiency and cores for performance is going to make a difference, then what exactly will the efficiency cores do that will be different from what the performance cores do?

[Vegan]

The CPU cores are pretty much the same as my lappy Celeron with Goldmont architecture with maybe a few tweaks to the instruction set. Hyperthreading is now gone for good.

The performance cores are simply using more power to get more work done.

[n_scott_pearson]

@Vegan is essentially correct. The Efficiency cores support execution using less power. Obviously, in order to deliver this capability, these cores support (amongst other things) only a subset of the capabilities of the Performance cores - and support for hyperthreading is typically one of the capabilities not supported. So, you have Performance cores, which are capable of supporting hyperthreading, and Efficiency cores, which do not support hyperthreading. This means that the number of threads that can be supported is twice the number of Performance Cores plus the number of Efficiency cores. For example, the Core i5-12600K has 6 Performance cores and 4 Efficiency cores. This means that is has 2x6+4 = 16 threads.

Hope this helps,

...S

P.S. For more information, I would start with this article: https://www.intel.com/content/www/us/en/gaming/resources/how-hybrid-design-works.html. 

[Vegan]

The hybrid approach is largely intended for gaming and other demanding tasks but when browsing the internet etc then the lower power cores kick in to reduce the thermal load.

This idea takes early power management to a new level with the upper priced processors. The cheaper models dispense with the lower power cores.