&gt; Large CPU usage slows down other apps - that&#x27;s one reason why I use ff instead of chrome.<p>The idea that apps should intentionally throttle their CPU usage to avoid &quot;slowing down other apps&quot; at the expense of performance is nonsensical. Apps should use all the resources in the machine to get the job done faster and go to sleep faster. The kernel, not userland apps, is responsible for multiplexing the system resources: that&#x27;s literally its job, and only it is in a position to do so properly.<p>&gt; I was pointing to the promise that it shouldn&#x27;t leak while it seems to be doing it seriously.<p>Nothing you&#x27;ve cited has been evidence of a leak. Adding a global garbage collector would do nothing to reduce the (non-)&quot;leaks&quot; you observe.<p>&gt; Have you heard about experimental features like pipelining and prefetch?<p>Enabling those via about:config tweaks and addons slows down your browser. Session and history limits do not affect your browser performance.