Im not sure why, they run the same engine, gecko. Trieddisabling HWA?

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems
• Upgrade your graphics drivers to use hardware acceleration and WebGL

hardware acceleration OFF

graphics drivers Updated

OS Tweak for speed ;)

Opera 12.16 runs circles around these two; but Opera has gone over to the dark side w/ Opera Next abomination based on chrome.

Everything that made Opera great is GONE!

Looks like Ghostery & Adblock Edge do cause some slow startups, but they keep the spyware ad junk away too!

I'm also using Memory Fox, Web Developer Toolbar, Ant-Adblock, Flashblock.

I don't need NoScript since I can do that w/ WDT ;)

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

The add-ons I need are the performance killers, but I need them to get the job done.

The all-in-one SeaMonkey Suite should be slower since it has so much more going on than separate Firefox & Thunderbird applications.

I like all the bells & whistles available for Firefox, but the performance is a real letdown.

There shouldn't be any difference in performance between SeaMonkey and Firefox when it comes to web pages because they both use the same rendering engine. It is when you start customizing a browser via extensions or otherwise that things are changing and a lot of extensions can have quite an impact on the performance. Extensions are mostly written in JavaScript code and that is always slower than C++ code that makes the most part of the internal code.

I tested Comodo IceDragon for a few days & found some add-on issues: "Memory Fox" did not work. "Web Developer Toolbar" had a dark background.

Speed wise it was a little faster after first; then it started getting slower & pausing on same pages FF did. I saw little reason not to slay the IceDragon...

It's not browser cache & history because everything is cleared when closed & then cCleaned.