Does [Cache blocks] in Performance means that blocks generated by Views are also cached? I am working on an old Drupal 6 project.
My goal is to boost the performance of the website as much as I can.
Among other things I have done, I have already enabled cache  

Configuration > Development > Performance  

My question is, does [Cache blocks] in Performance means that blocks generated by Views are also cached or I have to enable caching inside Views?
In D6 views caching you have two kinds of options


Cache your query results -- Length of time your raw query results should be cached
Rendered Output -- Rendered HTML Output to be cached


In Block Cache in Performance settings

Block Rendered HTML Output to be cached which will be same as view setting.

For best performance you should use Views Caching option since it provides query level caching as well as rendered output caching.