> But ~300ms server response times is nothing if your end user has to wait 5-6 seconds for the page to render due to suboptimal frontend code. True for a singl

> But ~300ms server response times is nothing if your end user has to wait 5-6 seconds for the page to render due to suboptimal frontend code. True for a single request, but once you start getting lots of concurrent requests all those ~300ms server response times start adding up quite quickly. When Twitter started out, their use of ROR wasn't a problem. Once the service started to become popular, however, it was.