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Yes. Their arch is just different, they where not affected by meltdown and the chances of a spektre exploit actually working are very small. I don't know why th

Yes. Their arch is just different, they where not affected by meltdown and the chances of a spektre exploit actually working are very small. I don't know why that is the case but basically amd is 99% free from this story.

repolfx 8y ago
They aren't. Spectre works fine on AMD. They avoided Meltdown only because their cores are less optimised. Meltdown isn't Intel specific - Apple cores were also affected. It's clear that AMD weren't doing anything special w.r.t. side channel attacks. They were just further behind in the optimisation race and as a consequence, were less hit.
- likeclockwork 8y ago
  Can you really call "fast but wrong/insecure" optimized?
  - mark-r 8y ago
    Yes you can, if it makes your benchmarks look better. That's why Intel is trying to suppress the benchmarks.
  - Dylan16807 8y ago
    It doesn't calculate anything wrong, so sure. For this particular optimization, it looks better not to have it. But in general, knowing how something is flawed lets you mitigate the flaws. We use floating point despite it being mathematically wrong, because it's fast and we can mitigate the wrongness. I could imagine a chip where speculation could be toggled between different modes, if there was enough demand. I will say that "just further behind" is probably wrong. AMD has a lot of optimizations in their chips. They have safer ones, which might be luck or might be engineering talent, but it's not a mere artifact of being behind the curve.
- kllrnohj 8y ago
  That is a horrifically biased & wrong summary. AMD enforce privilege checks at access time rather than at retirement time. Whether or not this is due to "lack of optimization" or "good security engineering" nobody knows. But your claims that this was purely the result of "less optimised [sic]" cores is nonsense. You have zero evidence whatsoever that that was the case vs. AMD just having superior engineering on this particular aspect and not adding bugs to their architecture. All we know are that Intel & ARM CPUs have an entire category of security bugs that AMD don't, and that upon close analysis AMD's CPUs are operating in a more secure foundation.
  - noobermin 8y ago
    Minor tidbit, but "optimised" is correct British spelling, so the disdainful "[sic]" is not needed.
  - repolfx 8y ago
    The summary is correct and optimised is the correct spelling where I'm from. If AMD were making conscious efforts to avoid side channel attacks they'd already have had various features to show for it like IBRS. But AMD's chips say nothing about side channel attacks. Their manuals do not discuss Spectre attacks. And there is no evidence anywhere that they knew about Meltdown type attacks and chose to avoid them. I get that suddenly hating on Intel is cool and popular, but the facts remain. There is no reason to believe AMD has any advantage here.
    - kllrnohj 8y ago
      For meltdown AMD followed what the x86 spec said. It's flabbergasting you are trying to contort this into making AMD look bad. Your "summary" was basically that AMD was too incompetent to have multiple security issues. The facts are AMD does not have a significant per-core IPC defeceit vs. Intel (as supported by every ryzen review at this point) and AMD has, on multiple occasions now, had objectively superior security. You're trying to twist this into a negative against AMD. It's nonsense FUD. Intel fucked up, AMD didn't. Why are you trying to run PR damage control for Intel?

repolfx 8y ago

They aren't. Spectre works fine on AMD. They avoided Meltdown only because their cores are less optimised. Meltdown isn't Intel specific - Apple cores were also affected. It's clear that AMD weren't doing anything special w.r.t. side channel attacks. They were just further behind in the optimisation race and as a consequence, were less hit.

likeclockwork 8y ago
Can you really call "fast but wrong/insecure" optimized?
- mark-r 8y ago
  Yes you can, if it makes your benchmarks look better. That's why Intel is trying to suppress the benchmarks.
- Dylan16807 8y ago
  It doesn't calculate anything wrong, so sure. For this particular optimization, it looks better not to have it. But in general, knowing how something is flawed lets you mitigate the flaws. We use floating point despite it being mathematically wrong, because it's fast and we can mitigate the wrongness. I could imagine a chip where speculation could be toggled between different modes, if there was enough demand. I will say that "just further behind" is probably wrong. AMD has a lot of optimizations in their chips. They have safer ones, which might be luck or might be engineering talent, but it's not a mere artifact of being behind the curve.
kllrnohj 8y ago
That is a horrifically biased & wrong summary. AMD enforce privilege checks at access time rather than at retirement time. Whether or not this is due to "lack of optimization" or "good security engineering" nobody knows. But your claims that this was purely the result of "less optimised [sic]" cores is nonsense. You have zero evidence whatsoever that that was the case vs. AMD just having superior engineering on this particular aspect and not adding bugs to their architecture. All we know are that Intel & ARM CPUs have an entire category of security bugs that AMD don't, and that upon close analysis AMD's CPUs are operating in a more secure foundation.
- noobermin 8y ago
  Minor tidbit, but "optimised" is correct British spelling, so the disdainful "[sic]" is not needed.
- repolfx 8y ago
  The summary is correct and optimised is the correct spelling where I'm from. If AMD were making conscious efforts to avoid side channel attacks they'd already have had various features to show for it like IBRS. But AMD's chips say nothing about side channel attacks. Their manuals do not discuss Spectre attacks. And there is no evidence anywhere that they knew about Meltdown type attacks and chose to avoid them. I get that suddenly hating on Intel is cool and popular, but the facts remain. There is no reason to believe AMD has any advantage here.
  - kllrnohj 8y ago
    For meltdown AMD followed what the x86 spec said. It's flabbergasting you are trying to contort this into making AMD look bad. Your "summary" was basically that AMD was too incompetent to have multiple security issues. The facts are AMD does not have a significant per-core IPC defeceit vs. Intel (as supported by every ryzen review at this point) and AMD has, on multiple occasions now, had objectively superior security. You're trying to twist this into a negative against AMD. It's nonsense FUD. Intel fucked up, AMD didn't. Why are you trying to run PR damage control for Intel?