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by aeiou1234 2403 days ago
another 0-4% performance hit for skylake
3 comments

The really damning part is that it applies even for processors that are supposedly fixed in silicon because Intel dropped the ball by playing wack-a-mole with proof of concept exploits instead of thoroughly building their chips with security in mind.

If the history of Microsoft and Windows security is any indication, it'll take Intel many many years to turn that ship around.

There's a question of whether AMD has been mostly unaffected only because their chips haven't received as much scrutiny, but for the time being it does seem that if you care about security, you'd better go with Epyc.

I don't think anyone seriously expected Intel to be able to thoroughly harden their chips against Spectre-style attacks given just a year to tweak their existing microarchitecture. They were able to move some permissions checks ahead of some speculative actions, but they simply haven't had enough time to design an architecture that can unwind all observable side-effects of mispredictions. It was obvious that all the near-term fixes in silicon would be equivalent to or only slightly better than the microcode or OS-based mitigations.
AMD’s speculative execution design is more risk aversive and it isn’t prone to many of the bugs identified so far. Of course this may change but I think it’s more than just scrutiny: AMD speculates less.

Plus, with better IPCs on Ryzen and much greater performance per dollar, why Intel?!

> If the history of Microsoft and Windows security is any indication, it'll take Intel many many years to turn that ship around.

AMD's Bulldozer debacle may be a better example, because in some ways it's a better example than Windows.

By that, I mean two things.

1) Silicon typically has a pretty long up-front design phase. Meaning there's probably at least 2 upcoming generations in development at any given time.

2) Intel's marketing is somewhat coy about 'architecture' changes, but the sources I found (admittedly just an SO post and Wikipedia) indicate that the number of pipeline stages in the Core series has not changed much over the last few years. IOW it's probably not a full architecture revamp in their 3-step cycle.

P6 as an Arch lasted around 15 years, when you think about it (including the original 'Core' i.e. Core 2 Duo/Solo here, as while heavily optimized and revamped, it was still P6). K7/K8 lasted about the same longer (15-ish). Netburst was a bit of an outlier, only lasting around 7 years. Same for Bulldozer.

Big assumption here, but based on the pattern I'd assume that Intel originally wasn't even considering a full revamp (or, depending on how they do their iterations, it wouldn't be fully revamped) to be ready until around 2023.

Because of the time involved (back to the first point,) I doubt they would be able to have the problem mitigated in silicon until 2021 at the earliest. (As a bonus, they'd probably want/have to qualify it extra well, lest they accidentally introduce a whole new class of vulnerabilities.)

What are we down to now? 70%? 80%? of original performance with all the mitigations added up by now?

If a car was advertised as emitting 20% less pollution than it actually did, people would be pissed[1]!

[1]: https://en.wikipedia.org/wiki/Volkswagen_emissions_scandal

I'm glad I started off not overclocking my 6700k with the intent of cranking up the clock over time in order to maintain the same performance with regard to software bloat and mitigations like these. I got lucky and can hit 5Ghz safely, with a base of 4Ghz.

Definitely jumping to AMD next time around though. My next upgrade was originally going to be dual Xeons but those Ryzen Pro 3000s are looking nice.

Yeah I'm looking into upgrading my 6500 to a Ryzen 3 3600. It's a shame there's no B550 boards yet.
From what we've seen so far B550 is pretty much just x470 (no PCIE4). And B450, B350 boards will do fine running a 3600. I don't really see a point waiting for B550.
It's mostly just that I'm afraid I'll order a board that isn't on the latest bios, which will be a headache.

And an excuse to postpone.

Some MSI motherboards (and maybe others?) have a "Flashback" feature to flash BIOS from a USB storage device without needing a CPU.
I was completely unaware of this feature, and blissfully saved by it when building a computer for a family member. It's a killer feature.
Oh nice, I had no idea. I might pull the trigger on black friday then.
Can confirm, mine supports this.