Drupal chat slowdown my application I am using Drupalchat for my application. The issue is that my application getting very much slow down after put this chat system. I think the problem will be due to Ajax, it's keep on polling to the server for frequently to check the chat messages(incoming or outgoing). How to fix this issue to fasten my application ? 

Also I am curious about how the facebook and gmail chat systems are working in general?
AJAX chats are pretty resource hungry by nature when running on Apache, so there are no easy configuration switches that will instantly give you better performance, I'm afraid.

The big difference between chat implementations is that GMail and Facebook uses a different backend, more suitable for AJAX polling / push. The node.js backend for Drupalchat might be able to help you in that regard. If I were writing my own chat from scratch, I'd probably try out http://www.ape-project.org/ which seems to be pretty good featurewise.