PHP, download thread safe or non thread safe?

When you download PHP 5.3.10 from:
 http://windows.php.net/download/

You can see  "VC9 x86 Non Thread Safe" and "VC9 x86 Thread Safe".
Which one to use?
 From http://www.sitepoint.com/install-php53-windows/, the advice is:

"A Thread Safe version should be used if you install PHP as an Apache module. The Non Thread Safe version should be used if you install PHP as a CGI binary."

The reason is that  when we use Apache http server, we normally use mod-php. The PHP is loaded into Apache as threads. So we need thread safe  PHP  for Apache.