Sorry if that's a duplicate but I couldn't find anything about scaling the number of web/content processes we use with e10s. At the moment we use a single content process which probably isn't the configuration we want to ship. How about starting with one content process per browser window? That sounds like safe number of processes and might unveil some bugs earlier. That is of course assuming that tabs showing pages of the same host in different windows don't need to be in the same process? Feel free to close if it doesn't make sense :)