At first I found my OTA installation of Froyo mediocre, and noticed no improvement and possibly a decline in internet browsing performance. I changed plugins to "on demand" with little effect. I did a hard reset, which GREATLY improved things, but after awhile, things seemed to be getting worse, and eventually the browser would sometimes just partially download a page and almost freeze incomplete. Sometimes the page would eventually pop open abruptly, but more often I lost patience and closed the browser. I soon got a message (I don't remember the exact words unfortunately) saying that dictionary.com was causing a problem, and encouraging me to force close it. Naturally, I did, and browsing performance improved greatly! I'd had Dictionary.com installed, and had been using the word of the day widget from them. I uninstalled both, and performance browsing was better than it had ever been. This went on for a couple of days, and I decided that I must have been over-reacting on Dictionary.com, so I installed the application and the widget again. Browsing performance slowly deteriorated, over enough days that I forgot about the reinstalled application. Today things became intolerable, the browser was stalling out regularly on web pages of any size, and not doing too well on mobile webpages. Early this evening, I got a familiar error message, warning me that Dictionary.com was causing problems, and inviting me to force close it. I did so, and immediately went to uninstall the app and widget. Once again, browsing performance improved significantly!
This probably only affects a few people, but if your browser performance is sluggish after Froyo, and you have Dictionary.com installed, try uninstalling it! To my knowledge, I never had this problem on 2.1.