It worked for one SKU at launch and by disabling up to 50% of the cores of the others. Calling that a working feature is a bit of a stretch already.
I don't know if it was super good (Linus Torvalds certainly was loud against it, and from his POV, his critic makes lots of sense), but I run some numeric code from time to time that _in theory_ could benefit from it. So it's a bit of shame that it won't be supported in future products? Let's see what AMD does about it on Zen 4 and if they manage to force Intel back to it, if only for competitions sake.
[0] https://travisdowns.github.io/blog/2020/08/19/icl-avx512-fre...
My comment was about Alder Lake, where only P-cores even have AVX-512 units.
The i9 has 8 P-cores and 8 E-cores and users need to disable the 8 E-cores to use AVX-512. That's 50% of the cores gone for very niche use cases.
Considering that the PS3 emulator only got ~10% better performance on the highest end, it'd be better to simply get an 11th gen high-end part instead of a lower end 12th gen CPU for that use case anyway, so I really don't understand what the fuss is about.
Even then, you're not turning off half the cores:
* Area wise, 4 E-cores use as much die space as 1 P-core.
* Thread wise, turning off the E-cores brings you from 24 threads down to 16 threads.
* I didn't see the PS3 emulator benchmark, but you are telling me that they got a speedup.
* There are some anecdotal accounts ("hardware influencers", YouTube channels, etc) about P-cores being the main driver for gaming performance, hence why these sources mainly recommend the 12400 processor with no E-cores as a price/performance sweet spot.
* Of course, not everything is gaming, and depending on what you do with your computer(s), what will work better.
All in all, I'm more interested in the Celeron/Pentiums which will be Gracemont only (E-cores) and what kind of performance, battery life they get from them. I have an old (2018) sub-notebook that houses an N4000 Celeron (that'd be Goldmont+), and it was surprisingly good for answering emails, web browsing and watching online video. Abysmall performance if you tried to do anything that required math with it (10x to 100x slower than an i5 from the same time) but apparently they've ironed out all those things and those little cores can get in the same ballpark performance, at a much lower power envelope.