not possible to call CI controllers simultaneously?

[eluser]Crafter[/eluser]
I don't think its true that CI will disallow simultaneous calls. (Theoretically) Each call is made as a seperate call to your web server, who then hands this off to your CI application. The web requests work in a connection-less environment - that it - the webserver connects, sends the data, then disconnects from the browser.

I'd like to ask why you are doing an infinite loop. It is perhaps not your browser that is spending CPU time in the loop. The Prototype ajax library has a way of periodically sending Ajax requests without sitting in a tight loop. Not sure which Javascript library you are using.