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."
> "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....
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/