Ok, this time i tried with KVM - still crashes. And RAM, both with VirtualBox and KVM, was set to 512 MB. This time it didn't get to "Where are you" screen and the following text was in expandable area:

rocess 2830 (n/a).
Apr 26 16:15:26 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:15:51 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:15:51 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:15:51 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:15:51 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:15:51 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:15:51 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:16:02 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:16:02 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:16:02 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:16:02 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:16:02 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:16:02 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:16:13 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:16:13 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:16:13 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:16:13 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:16:13 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:16:13 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:17:09 ubuntu CRON[6726]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Apr 26 16:17:56 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:17:56 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:17:56 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:17:56 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:17:56 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:17:56 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:18:36 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:18:36 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:18:36 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:18:36 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:18:36 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:18:36 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:18:55 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:18:55 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:18:55 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:18:55 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:18:55 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:18:55 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:20:26 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:20:26 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:20:26 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:20:26 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:20:26 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:20:26 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:20:55 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:20:55 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:20:55 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:20:55 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:20:55 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:20:55 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
Apr 26 16:21:05 ubuntu rtkit-daemon[2833]: The canary thread is apparently starving. Taking action.
Apr 26 16:21:05 ubuntu rtkit-daemon[2833]: Demoting known real-time threads.
Apr 26 16:21:05 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2921 of process 2830 (n/a).
Apr 26 16:21:05 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2919 of process 2830 (n/a).
Apr 26 16:21:05 ubuntu rtkit-daemon[2833]: Successfully demoted thread 2830 of process 2830 (n/a).
Apr 26 16:21:05 ubuntu rtkit-daemon[2833]: Demoted 3 threads.
/usr/lib/ubiquity/ubiquity/frontend/gtk_ui.py:1350: GtkWarning: IA__gtk_progress_set_percentage: assertion `percentage >= 0 && percentage <= 1.0' failed
  self.install_progress.set_fraction(fraction)
Apr 26 16:22:22 ubuntu ubiquity[3070]: debconffilter_done: ubiquity.components.install (current: ubi-timezone)