From what I can gather, one of the 3 issues found is Intel-only, very bad and very easy to exploit, and can be patched with a large performance hit.

Another is harder to exploit, and has no known workaround (likely requiring new silicon to fix), and affects basically all micro-architectures in use today, including AMD's x86 silicon.

The third, I know nothing of.

Ah, it must be serious, there's now a branded website [1] for it ;)

I believe the Intel only issue is called "Meltdown" and the second is called "Spectre"; the attack website [1] has details of both.

[1] https://meltdownattack.com/

Reading the Meltdown paper [1], it's not clear why I keep seeing people say it's Intel only. The paper says quite clearly that other vendors' processors could be affected:

"Instead, Meltdown exploits side-channel information available on most modern processors, e.g., modern Intel microarchitectures since 2010 and potentially on other CPUs of other vendors."

[1] https://meltdownattack.com/meltdown.pdf

> "Instead, Meltdown exploits side-channel information available on most modern processors, e.g., modern Intel microarchitectures since 2010 and potentially on other CPUs of other vendors."

But their website faq says[0]: every Intel processor which implements out-of-order execution is potentially affected, which is effectively every processor since 1995 (except Intel Itanium and Intel Atom before 2013). .... Currently, we have only verified Meltdown on Intel processors....

[0] https://meltdownattack.com/#faq-systems-meltdown