Since it wasn't originally clear to me, I'll pass this on. The word "microarchitectural" is code for "the implementation of an architecture/design". When someone says that the fault is in the microarchitecture, it means that the design was fine. They just implemented it badly.
This is important when reading documents about Intel's speculative execution issues.
Ars has a good description of Architecture vs Microarchitecture in the "Recap" section of this article. https://arstechnica.com/gadgets/2019/05/new-speculative-execution-bug-leaks-data-from-intel-chips-internal-buffers/
A bunch of technomancers in the fediverse. Keep it fairly clean please. This arcology is for all who wash up upon it's digital shore.