My understanding is that chip QA at Intel took somewhat of a nosedive post Haswell. From my ignorant but interested outsider perspective, everything from Broadwell on seemed to be a mess execution-wise compared to Haswell (modulo TSX), and _especially_ compared to Ivy Bridge.

Some of the recorded comments on https://danluu.com/cpu-bugs/ (First update section) mesh with my observations, but I wouldn't know enough to tell if I was on to something, or just confirming my own biases.

Intel willingly admitting mistakes is just about as likely as hell freezing over

It really is. I got hit pretty bad by an ubuntu intel-microcode package regression, which has this annoying property that soft reboots fail (and hard reboots are fine). I lost about 3 days of work to this[0], and our mitigation (pinning the package to an earlier version) is still painful, because you have to go through one OS installation cycle and still manually reboot (we do a lot of manual OS installations, and debugging "first installs").

Anyways I was bitching about this to my roommate, and she remarked that hey you know acquaintance X we know works in Intel software security division. I told her to give him crap about it and apparently his response was something like "we should have closed comments on that github issue". I feel like this is not a really appropriate response, even between friends.

AFACIT the package still hasn't been fixed and the official ubuntu solution is to roll back to the nonbroken version.

[0] admittedly slightly poor internal communication is also responsible, since this was observed by our support staff for our customers which didn't make it known to R&D - me

Which happened earlier today with Microsoft teams for linux