Hi customhitcher, Firefox is a multi-process application. This improves stability against crashes and isolates the memory of different websites for data safety. To see which process is using the most resources, check out the built-in Task Manager at Shift+Esc (or you can type or paste about:processes in the address bar and press Enter to load it). If a particular website is at fault, or one of your add-ons, this tool should help in tracking it down.

Hi There, Thank you for reponding. I know Firefox is a multi-process application, and has been for a long time, but the problem is how it is using RAM now and it is recent. I've add a screen shot of it, I am using Windows 10 Pro and using the 64 bit side of it as I switched to almost all 64 bit programs. Yes I still have lots of older 32 bits programs as most do. So My Problem is firefox using so much RAM now. 1 GB of RAM is way to much. Sorry my machine will not do the full 16 GB of ram, still trying to figure that out as the pervious machine had no problems with 16 GB of ram. SO I'm stuck with 8 GB plus the 16 GB cache on the SDD. If you need more info on about this old machine?please let me know. I'm Doing this with 2 tabs open, one is my email and this one. Thank you for your help in this wierd problem. Dennis

That seems like too much memory for two tabs. (I have 60 windows open with lots of tabs per window and total memory use is about 3900MB.)

If you check the "All Tabs" drop-down at the upper right, does it list any hidden tabs?

Do you see all 13 processes on the about:processes page (Shift+Esc)?

You also could look at the about:memory page and try some of the tools there. Please see the following article for tips: Firefox uses too much memory or CPU resources - How to fix.