Which cache is working with cwp apache using suPHP?
Nginx as revers proxy will also help as it will be used for all static file and will provide better stability and lower number of request for apache.
PHP-Switcher and PHP-Selector are using suPHP handler
PHP-FPM Selector will work with any cache
Varnish will work with suPHP (recommended)
Memcached will work with suPHP
Redis cache will work with suPHP
opcache will NOT work with suPHP (works with php-fpm selector)
xcache will NOT work with suPHP (works with php-fpm selector)
apc cache will NOT work with suPHP (works with php-fpm selector)