Sorry, not the sort of question likely to get a proper solution. I think everyone is reluctant to make a stab at providing any sort of answer. Far too many variable involved, and only a few seconds difference. I could suggest a few things that may shed some light on the issue but you wont necessarily get to the bottom of this. Turn on Firefox Health Report (fhr) *See [[Firefox Health Report - understand your browser performance]] That will enable you to get some hard facts. There are some experiments you could try to compare startup times, and try to figure out some of the factors causing the difference. Its also a good idea to turn on telemetry so engineers can collect anonymised data on Firefox performance. * [[Send performance data to Mozilla to help improve Firefox]]