I leave FF up (2 windows and about 30 tabs) on non-graphic intensive websites and within two days, the CPU usage climbs to well over %100, FF slows to a crawl and memory usage climbs to nearly 5G! I visit a lot of text sites, so most of the tabs are usually not graphics intensive. Even after I've left commercial sites and I'm not downloading anything, the memory and the CPU still continue to climb. When I quit and reopen FF, this will initially bring the memory and CPU usage down, but it inevitably climbs up quite quickly, regardless of my tab usage. Within 48 hours FF is unusable. I've tried all the suggestions in the support articles: I upgraded FF several times and the problem persists in each new version since about 26.0 or 27.0 I've cleared cookies multiple times, I've emptied the cache, I cleared my download history, and a majority of my browsing history, I created and switched to new profile, I've turned hardware acceleration for both Flash and FF on and off, I have tried resetting firefox to factory reset. I disabled my 3 plugins (Quicktime, Shockwave, and Java applet) I disabled my only extension (TabMixPlus) I restarted FF in Safe Mode - this helped but did not solve the underlying problem: the CPU usage and memory leaking still climbed without limit. The only difference was that it took several days longer to reach %100+. I tried about:memory to cause GC, CC, and Minimize memory usage - memory fell a couple hundred K and then resumed climbing. Interesting...in researching this complaint I tried the about:memory page again. I saw that 2 of my tabs (personal websites with textual technical blogs) were using 1.5G each. I closed those tabs and then Minimized Memory Usage. The total memory usage remained at 4.6G but 3.3G of memory was shifted to the 'Decommitted" pile (js-non-window/gc-heap/decommitted-arenas). I've seen this pattern before, memory is collected in some way but not truly released I infer. At this point the CPU usage also dropped from an average of %70 to about %45. What can I do to really fix this problem?