Which version of php to chose

I am planning to install latest php version 5.3.4 but bit confuse that which installer should I download Safe threat or non safe threat, either VC9 or VC6. Which one should I download from php.net ?

Difference detail is listed in this link http://www.iis-aid.com/articles/my_word/difference_between_php_thread_safe_and_non_thread_safe_binaries
 

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