Huh! I wouldn't expect that at all... here are some easy things to try: https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix https:

Huh! I wouldn't expect that at all... here are some easy things to try: https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix https://support.mozilla.org/en-US/kb/firefox-uses-too-many-c... If it is still happening after you try those, use https://perf-html.io/ https://perf-html.io/ and share a profile.