Mozilla Firefox 4 beta - first impression

The beta version of the new Mozilla Firefox can be downloaded from this page. Once you download the 8.96MB file, the installation procedure goes smoothly and Firefox 4 beta is installed beside your previous browser version, and you are asked to close the running instance of Firefox before opening the new one.

I'm testing it on an old Compaq EVO (Celeron 1.6GHz; 736MB RAM) running MS Windows XP Home Edition SP3.

The browser is loaded and running in half the time if compared to Firefox 3.6.6.

I have 15 extensions enabled on Firefox 3.6.6, 9 of them are disabled on Firefox 4 beta

• AddThis 3.0.1
• Firefox Showcase 0.9.5.5
• Firefox Synchronisation Extension 7.3.2.26
• Forecastfox 0.9.10.2
• Google Shorcuts 2.0.6
• Microsoft .NET Framework Assistant 1.2.1
• PDF Download 3.0.0.1
• Read It Later 2.0.6
• SearchPreview 4.4

 while Feedback 1.0rc1 has been added. I guess updates will come shortly.

A website heavily based on MS Silverlight like www.rai.tv/dl/RaiTV/diretta.html (live tv broadcasting) required to re-install the plug-in, then everything works.
I've surfed to several web-sites and all of them are rendered properly, though I'm not feeling improvements in terms of speed.

According to MS Windows Task Manager, Firefox 4 beta (8 websites in different tabs on one window) sucks from 10,000 to 40,000 K more memory than Firefox 3.6.6.

Coming back to Firefox 3.6.6, it inherits the last session of the last browser.

A specs comparison between Firefoxes is here.