Switching to memcache for sessions

Thanks for replying to my query!

I see that in Session_files_driver it does;
ini_set('session.save_path', $this->_config['save_path']); // setting the php.ini

But does not do anything similar in Session_memcache_driver.
I tried adding it in the __contruct but that dint work.

Im using CI version 3.3.0

True it does not call ini_set('session.save_path', ..., but it doesn't need to.
The Memcached driver does not use 'session.save_path' from php.ini. It only needs/uses a value from $this->_config['save_path'].

Is it not working using just the $config items?