我用的是ubuntu8.10 前幾日用了3d桌面，當時沒太注意問題是如何引發的，總之，最後是每次一重啟電腦，3d效果就沒了，還要重新設置，今天有點時間，在百度上搜了一下，解決了，轉載出來，希望幫助更多朋友解決問題：
百度：ubuntu 3d效果 重啟消失
在一個外文論壇上找到的，主要操作就是：
執行：gksu gedit /usr/bin/compiz
編輯文件的最後一行，在適當的位置加上：--indirect-rendering 保存即可
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轉載原文：
This isn't really a real answer... I mean it'll get the job done... but there you have it.
gksu gedit /usr/bin/compiz
right at the very bottom it says:
${COMPIZ_BIN_PATH}${COMPIZ_NAME} $COMPIZ_OPTIONS "$@" $COMPIZ_PLUGINS || exec $FALLBACKWM $FALLBACKWM_OPTIONS
Try:
${COMPIZ_BIN_PATH}${COMPIZ_NAME} $COMPIZ_OPTIONS --indirect-rendering "$@" $COMPIZ_PLUGINS || exec $FALLBACKWM $FALLBACKWM_OPTIONS
In place of it.
This changes what it run at the end so even if the script sees that you should run with direct rendering, the final exec line has it within. Easier than hacking up the actual script.
注：本文來源利納克斯的賽迪博客！