I tried to start my Firefox 3.5 in a safe mode (all add-ons were disabled) yesterday, in order to test if the mentioned performance problem (related to the browser, not BrainKing) would happen again. Now, after more than 24 hours, everything is still very fast and Firefox does not consume any system resources when it is idle (compared to 50% before).

Well, that means that it must be one (or more) of Firefox add-ons that causes the mysterious CPU load. The only problem is that I use about 15-20 of them, so it can take some time to find out the source. But I will try.

Anyway, if you still have problems to use BrainKing with Firefox 3.5, either try to start it in a safe mode or use another good browser (Google Chrome, for instance).