Its not the language but your framework and architecture and your own proficiency in the language ( whatever that might be) that matters most for a fast web application.
Your code would spend most of its time fetching stuff from DB, external web services etc and rendering HTML. Does your framework allow you to easily incorporate database caches? Does it allow to to cache frequently rendered HTML segments ? Can you offload certain tasks ( such as sending email etc.) to a secondary process via a job queue ?
You could write a web application in C that could still suck big time unless you get the application architecture right.
Your code would spend most of its time fetching stuff from DB, external web services etc and rendering HTML. Does your framework allow you to easily incorporate database caches? Does it allow to to cache frequently rendered HTML segments ? Can you offload certain tasks ( such as sending email etc.) to a secondary process via a job queue ?
You could write a web application in C that could still suck big time unless you get the application architecture right.