Im not sure when, but probably after I updated my Firefox from v1.5 to 2.0, I
experienced sluggishness whenever there's Flash contents in websites.

I realised the quality is set to high by default. And that caused the
sluggishness. How to configure the quality setting so that I can change it to
Medium as default? Because whenever I change manually by right clicking on the
flash content as set it to 'medium', if i close the broswer and reopened (or
even refresh the page), the quality flash content is set to high again as
default.

anyone can help me with this? Thanks

This isn't just an issue with FF2. I have experienced this issue on both FF 1.0.5 and 1.5.

The more flash content, the worse FF responds.