Bloqs is a complicated add-on. If you have an entry with a Bloqs field that has 10 bloqs, and each bloq has 5 atoms (custom fields), you're effectively rendering 50 fields to in a template. If each of those 10 bloqs has a Relationship field, then you're rendering 10 Relationship fields on the front-end of your site. These complicated field types (any fieldtype that is not a basic text, textarea, wysiwyg, radio, checkbox etc) can add considerable overhead. Below is an example of a profiling output from a cached and uncached Bloqs field render: