Requesting explanation of options in Black Mesa tab

I’d like to get an explanation of the various things in the Black Mesa tab of the options menu. Some things are self-explanitory, but some things aren’t. In particular I’d like to get an explanation of the items in the performance and visuals categories.

Thank you to anyone who can answer.

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.