If Firefox becomes slow or even unresponsive on pages with Chinese / Japanese symbols
(for example Google 资讯 or 日本 - Wikipedia)
try installing packages:

ttf-wqy-zenhei
wqy-bitmapfont


from Index of /repositories/home:/swyear/openSUSE_11.1

In addition, after installing these packages,
Chinese symbols in Firefox become a little bit more readable (as it seems to me).