Previous versions of Anki on Windows could cause delays when using wifi, due to an issue in the toolkit. If upgrading from a previous version, please uninstall Anki before installing 2.0.51 or 2.0.52. If you updated without uninstalling, please uninstall Anki, then install it again.
The toolkit Anki 2.0 uses becomes very slow when you use Thai text. The alternate installer available on the download site uses a different toolkit version which does not suffer from this problem.
Please use the alternate installer on the website if you are still using Windows XP.
If you experience crashes, please try the alternate installer.