Some tips about the ICS emulator;
1) Don’t expect it to run well on any machine with less than 3GB of RAM. It can be done, but don’t rely on it :).
2) There is a list of know issues in the emulator at http://tools.android.com/knownissues (from @ediTLJ on twitter)
3) Increase the default RAM for your AVDs to 1024MB (yup, 1GB)
4) If the emulator has crashed try deleting the AVD you used. If you’re told the AVD is in use then you’ll need to create a new AVD.
5) If you’ve hit problems with Snapshot set to Enabled on the AVD then turn it off.
6) Try setting the Max VM application heap size to 40MB or more (from +Reuben Scratton )
7) If your first boot appears to lock up it could be your contacts database. Try exiting the emulator and re-starting it (from +Reuben Scratton )
8) The screen resolution for the Nexus Prime is listed as WXGA720 in the AVD settings.
9) If you want to see what ICS will look like on a tablet use WSVGA or WXGA800 as the resolution.
10) The software buttons for Home, Back, etc. don’t appear to be in the ICS image for some resolutions. Resolutions known to support the soft buttons are WSVGA and WXGA800.
11) You should recreate any new snapshots in the new emulator. The emulator snapshot format has changed and the emulator doesn’t fail gracefully if it encounters a format it can’t use (from Xavier Ducrohet )