For example, you have 1000 torrents. As result, front-end must construct a table with 1000 rows for visualization. This is a very slow process. For avoid this, front-end really construct a table with min("Virtual Row Threshold",1000) rows. And draw ather torrents... hmm... my language is too bad for describe this process. Try to set "Virtual Row Threshold" to half of existing your torrents count and try to scroll torrents list - you will see.