Difference from navigator.hardwareConcurrency

CPU Performance API is conceptually very similar to Hardware Concurrency API. The CPU Performance API specification defines the algorithm Computing Performance Tier Value in terms of "physical or logical" CPU cores, but in practice it appears that all implementations report the number of "logical" cores. Hardware Concurrency API explicitly states that it reports the number of "logical" CPU cores. Granted, the two APIs report different numbers, but it would be interesting to read a comparison between these APIs, since this topic is not covered by the explainer, to the best of my knowledge.

Previously, #1 discussed the correlation between CPU Performance API and CPU Performance API, with the conclusion being that the correlation between the number of CPU cores and number of GBs of RAM is very weak. Explainer even explicitly mentions Device Memory API as a source of inspiration for this API.

Start by reading the CPU Performance API explainer and the linked Hardware Concurrency API specification, then compare how each API describes CPU cores and the values they expose. Add a clear comparison covering the reported core counts and their relationship; the work is done when the explainer addresses this distinction.