Hacker News Reader

Comment by monocasa | Hacker News Reader

At the last minute they got strapped to efficiency cores (Gracemont) that didn't implement AVX-512, and the schedulers of OSes they cared about running couldn't handle heterogeneous core features. Because of that they probably didn't finish verification of AVX-512 on the Golden Cove cores.

View on HN

I bought my i5-12500 (that has no Gracemont cores) just when it came out. Linux reported all kinds of AVX-512 extensions and I could transcode video with Handbrake using AVX-512 without any problems.

Later on Intel pushed a microcode update, and now my CPU doesn't have AVX-512 enabled anymore.

microcode updates are volatile, you can rollback your microcode package in your distro and get the capability back. Some BIOSes also apply microcode. If you updated your BIOS, roll that back instead.

I updated my BIOS, and I'd rather have security fixes than AVX-512 that I don't really need because all I do with this machine is surfing the internet and watching movies. Thanks for the tip nevertheless!

I was just referring to OP who said that Intel probably didn't verify AVX-512 thoroughly, because it seems they did.

It's amazing to me that Intel can - without being held accountable, and for obvious strategic commercial gain - disable vital, working functionality in products they've already sold through the use of combined updates which are otherwise legitimately meant to address things about their products which are dangerously broken. Apply them and lose the function or be vulnerable and unstable. They can't keep getting away with this, and yet, they do.

In this case AVX-512 was never advertised so Intel feels justified in removing an "easter egg".

I mean, most vehicle manufacturers don't advertise that their transmissions have a 'reverse' gear but it doesn't mean they can just remove it using a software update...

Reply on news.ycombinator.com