Which sql server driver (sql server 2008) should be used for PHP 5.3.8?

Which sql server driver (sql server 2008) should be used for PHP 5.3.8, and why? There are 4 options in the download (http://www.microsoft.com/download/en/details.aspx?id=20098), php_sqlsrv_53_nts_vc6.dll, php_sqlsrv_53_nts_vc9.dll, php_sqlsrv_53_ts_vc6.dll, php_sqlsrv_53_ts_vc9.dll. The vc6 versions don't work (running sugar CRM), so vc9 is probably what I need. I want to understand wh开发者_JAVA技巧y.

This depends on your php version, last time I downloaded the driver there was a readme the described the choices: Php is either thread-safe or non-thread-safe (ts or nts) and compiled using Visual C 6 or 9. You find these Information in the output of phpinfo().