 <p>Install the New Relic Standard addon - that will give you insight into your application and what's going on. The 'Dynos' tab will show you memory utilisation of your application, it sounds like an awfully high memory utilisation for the level of traffic you're reporting but it depends on your application - if you're seeing memory errors in the log then performance will be suffering see <a href="http://devcenter.heroku.com/articles/error-codes#r14__memory_quota_exceeded" rel="nofollow">http://devcenter.heroku.com/articles/error-codes#r14__memory_quota_exceeded</a></p> <p>Are you using any kind of error handling? You could install the Airbrake addon so you get notification of errors or use the Exception Notifier gem which will email you errors as they occur. Once you have these in place you'll know what's occuring - whether it's in the application or if you don't receive any then it's outside factors, like the visitors internet connection etc.</p>