Ask HN: Why Intel and AMD share the same design flaw? - fxbois
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lucozade
Because they are good ideas if you want your CPU to run fast.

The combination of features involved: caching, branch prediction and out of
order execution are all very valuable. Both individually and in combination.

What has been discovered is that, under certain circumstances, they combine in
ways that can leak sensitive information. This is a very bad thing and needs
mitigation/fixing.

However, it doesn't mean that the underlying features are inherently bad. Just
that they have complex interactions that aren't as well understood as,
perhaps, was thought.

When this all settles down, I wouldn't expect these features to be removed.
Rather they will be constrained such that they retain as much performance as
possible but without the security implications.

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samfisher83
Its how processors are designed. If you take a computer architecture class
which I am pretty sure most compsci people have done you learn about most of
this stuff. If you don't do caching, branch prediction, pre fetching, out of
order execution your processor won't be as fast. Someone just figured a way to
exploit the fact that processor are already loading data that it needs to
process.

If you are doing a laundry cycle and you have to wait for the dryer to to
finish before you load the washer its going to take lot longer to do the
laundry.

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stealthcat
>If you are doing a laundry cycle and you have to wait for the dryer to to
finish before you load the washer its going to take lot longer to do the
laundry.

Reminds me of that lecture notes slides from MIT OpenCourseWare on digital
electronics

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zelon88
I was under the impression that AMD chips weren't vulnerable to Meltdown or
variant 1 of Spectre. Only variant 2, Bounds Check Bypass, could be achieved
on an AMD chip.

Is that an incorrect impression?

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psyc
Essentially because it isn't a bug in the usual sense. It's a vulnerability
that is present even though the processors are doing their primary job
correctly.

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thomas
Was wondering the same thing! Experts please jump in.

