Even AMD admits their rdrand is broken and offers patches.
Test a bad AMD system by yourself. I have such a system, unpatched, and it's atrocious. Slow and Bad. But more atrocious is that systemd keeps on using this possible backdoor. It's bad and slow, most other LCG's are miles better.
https://rurban.github.io/dieharder/QUALITY.html
https://github.com/rurban/dieharder/blob/master/libdieharder... using the intrinsic, not inline asm
(1) There's no evidence of anything wrong with AMD's RNG.
(2) Lots of people on Github and HN don't understand the birthday paradox.