I have an old Win 7 laptop with very limited specs. I decided to use this version of FF (52.8.1) because I've used it before with no problems on an even older laptop with Win XP. However, the experience is not pleasant to say the least. I'm attaching here some screenshots so we can see exactly what's going on. First image: 2 tabs, Yahoo mail, calendar = 1 GB of memory, 59% of CPU. Second image: 3 tabs, Yahoo mail, calendar, FB = 1.5 GB of memory, 55% of CPU. Third image: 1 tab, blank, after closing the other tabs = 725 MB of memory, 52% of CPU(!) At this stage, the '''very latest''' version of Chrome is actually less resource-heavy than this version of FF. I went ahead and did an experiment: '''exact same 6 tabs''' in Regular Mode vs. Safe Mode with add-ons disabled. Fourth image: regular mode, 700 MB of memory. Fifth image: safe mode, 420 MB of memory. So, with all add-ons disabled, I save about 300 MB of memory, which is rather substantial (as a percentage) but not dramatic. I have "hardware acceleration" already disabled. Zero themes. My add-ons are very basic, an ad blocker, a translator, two pdf savers, a couple of video downloaders, and a cash back shopping button. Btw, I tried the "minimize memory usage" and it freed up only 150 MB, so almost useless. I realize this is a recurring issue with FF and that many people report usage over 4-5 GB of memory. But you can see I don't have that much RAM, plus I thought this older version would be "efficient" with Win 7. Thank you for any suggestions!