X86
The King for now
Intel
- http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html
- https://software.intel.com/en-us/intel-isa-extensions
AMD
- http://developer.amd.com/resources/documentation-articles/developer-guides-manuals/
Spectre: Secrets, Side-Channels, Sandboxes, and Security - 2018