Tables Make Slower Downloads
A single table on a Web page will not slow downloading. But the moment you put one table within another table, it gets more complicated for the browser to render, and so the page loads more slowly.
Nested Tables for Page Layout When you create a page with tables, keep in mind that the more tables that are within tables, the slower the page will load. Normally, when a page loads the browser starts at the top of the HTML and loads it sequentially down the page.
However, with nested tables, it has to find the end of the table before it can display the entire thing. Table Design If you design a table with multiple rows, it can often load more quickly if you write each row as a separate table.