0.6 introduced automatic image resizing (of IE6 fame) and smooth scrolling (of IE4+ fame). Many people find these features annoying, but it's not obvious how to turn them off. Since there are no options in the preferences dialog, you have to type about:config into the address bar and set them there. However, this isn't a particularly elegant configuration interface, as you can't search and it's a flat list (searching and trees would be nice). So here are the settings you have to turn off: browser.enable_automatic_image_resizing and general.smoothScroll.
MozillaFirebird? often feels snappier because it has nglayout.initialpaint.delay set to around 250ms, as opposed to Mozilla's 500-1200ms. This controls the delay between receiving intial page data and repainting, and is designed to give the web page layout time to settle so it doesn't jump around. By setting it lower, MozillaFirebird? feels slightly quicker than Mozilla. Some people set it to 0.
In address bar type: "about:config" (WithoutTheQuotes?).
Type "keyword" in the search box, then edit the value for "keyword.URL" to be: "http://google.co.nz/search?btnG=Google+Search&q=".
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