mysqli_free_result a no no?

[webdevindex]

Using mysqli_free_result is taking up more memory than not using it suprisingly.
Could anyone verify this? If so then why should anyone want to use it?
I'm using php 5.1. and testing by putting echo memory_get_usage() at the bottom of my scripts.

[Dan Grossman]

I would think you'd want to use it when making many queries with large result sets in a single script. Otherwise there's no benefit, as the resources will be freed when execution ends automatically.

[webdevindex]

Thanks for you input, here is a quote from php.net
"Note: You should always free your result with mysqli_free_result(), when your result object is not needed anymore."

echo memory_get_usage();
mysqli_free_result($res);
echo memory_get_usage();

The above scripts returns more memory usage for me after free_result is executed.
What is considered large result sets? LONGBLOBS?