Ok, I hope I won't get downvoted for this being not a coding question, but I think this will benefit all who want to make their Wordpress projects more CPU efficient.
Basically on the other questions that I asked, I got a response that it's better to use Custom Taxonomy (same as category or tags), rather than using post meta data.
My question is, is it really better for server CPU and if yes, that means Custom Taxonomy is working completely different than Post meta data query?
I'm building a quite serious project and I want to make it as efficient as possible, so that I wouldn't need to redo all over again.
To clarify, is custom taxonomy more efficient than post meta data when it comes to querying the posts. Thanks.