I have more than 100 tabs and more than 1k open in the background (the tab is downloaded from the previous session, but not open). When opening / closing the FF tabs, it gradually uses up to 18-20GB. When this limit is reached, friezes begin, the tabs open slowly. Memory busy FF is released ~2GB, after that it starts to load pages. According to symptoms, it looks like a shortage of RAM. But I have 64GB RAM, reserve (Win) 17GB, free 15GB. And more is 9GB SWOP on SSD, 136GB of free space on SSD and 1TB+ free space on HDD (RAID0), 200+ MB / sec internet . Where and what to change to ff used accessible resources? After all, they exist!