PHP FASTCGI turns off suddenly. How to fix it?

Question

PHP

Our server is running on Windows Server 2012.
Installed: nginx + php5.4 + mysql.
During server power testing with 'ab' or 'siege',
when 500 requests are made to the server, php-fcgi is disabled by itself.
nginx worker connections : 1024, worker processes: 7
Powerful server: 8 Intel Xeon cores, 16gb RAM.
I tried to change the version of the server and PHP, it did not help ((
How can I solve this problem? Have you had such problems?

Answer 1

Have you had such problems?

Well
confuses strongly
Config fpm what?