I have Firefox 58/64bit/Linux and it slowed down Firefox on my i5 with 16GB ram (2GB free) w/ HDD for about 1 second... it didn't lock it up because any action

I have Firefox 58/64bit/Linux and it slowed down Firefox on my i5 with 16GB ram (2GB free) w/ HDD for about 1 second... it didn't lock it up because any action that I did on firefox was slowed down by about 1 second... other programs seemed fine too.