I was and am curently using V.21 now. I had updated to the latest V.23 and it was absolutely horrible. Normaly, Firefox is the FASTEST of all mobile browsers on my HTC Rezound since the Android 4.0.3 update. But FF 23 has so much lag. The FPS seemed like it had been cut to half speed. The load times on full desktop facebook was ok, but scrolling and zooming speeds were unacceptable. Seemed like a frame limiter was put in place. Script loads were VERY slow. Scrolling felt like it was dragging a ball and chain around... uninstalled and went right back to V.21. oh what a relief that was lol....
I'm not facing any of these problems.
You can try with Beta version
Newest beta is a little better than V.23 , but still quite slow FPS with much screen blur scrolling and zooming. I can see a huge difference in scrolling/zooming speed when coming back to V.21 ...that is V.21 is much faster than V.23 and newest Beta. Newest beta also has similar loading time lag after scrolling like V.23 .Whatever you are using, your handset must have some different kind of CPU instruction set. Maybe its the Adreno GPU that a lot of these browsers dont think to optimise for. See, a lot of other people don't have the same problems I have with a majority of browsers since my Rezound got the ICS 4.0.3 update. I can't use the stock browser, Dolphin or Boat Browser on most websites because they lag and freeze like crazy unusable.... that's why I have stuck with Firefox only. And probably with V.21 for awhile til they get this straightened out.
Yes I have the issue as well. If I have ESPN radio playing in one tab the browser becomes nearly impossible to use!!
Sadly, my IE 10 is working faster and smoother than my FF 23. It's very sad to say cuz IE is super old and it should be laggy, but my FF 23 is laggy as hell. I thought at first it was because I upgraded my Adobe Flash player, but no, it's FF 23. It eats huge amounts off my CPU. I thought I could calm it down by using Firemin, but no. It eats about 700 K memory and with Firemin, it eats about 100 K - 200 K memory.
since this last update firefox has been painfully slow, even in safemode or when disabling the extensions. The CPU usage is often at 90% when it is literally doing nothing, and even after I close it firefox will still take half a gig or more of memory and 50% CPU cycles for hours after it has been closed - basically until I end-task it or reboot.