We can edit the GRUB config to start the Ubuntu from text interface, by doing this the performance should be better.
1 grant write permission to grub.cfg file
sudo chmod +w /boot/grub/grub.cfg
2 edit the cnfg file and add the text login
sudo vi grub.cfg
Add "text" at the end of this line:
linux /boot/vmlinuz-2.6.35-22-generic root=UUID=60944139-5f5d-4aa4-a0da-acc77766e0c6 ro quiet splash
3 remove the write permission for grub.cfg
sudo chmod -w /boot/grub/grub.cfg
4 reboot then we can login from the text interface
P.S.使用文本登陆的目的是为了节省系统资源，尤其是需要在虚拟机（vmware）里做测试的时候。今天换了文本登陆之后，vmware占用的内存才50M左右，远远小于图形界面的200-300M，基本上可以将vmware设成开机启动了。
