What do these Core 1-12 metrics tell me?
Mac mini 2018 i7 :: Sonoma 14.3.1
That’s a 6 core CPU with hyperthreading to create an extra virtual core for each real core. The odd-numbered cores are the physical cores and the evens are virtual.
The CPU is not using the virtual cores, for the most part, which is why the odd-numbered physical cores are the ones lit up. Green = user programs, red = system programs.
Whether Intel hyperthreading is actually helpful is complicated. It’s a minor speed advantage over execution threads defined in software, and only with certain kinds of parallelizable tasks. It’s not hurting your performance either, though.