teamanandtech.org

Due to increasing problems with a small group of users intentionally
  causing assigned work units to fail we’ve eliminated points for
  incomplete work units.  We’ve also imposed stricter requirements for
  bonus points.  Neither of these changes should affect normal users.

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CPU Folding on very high core count machines used to be plagued with failing workunits. Would be good if they fixed that (I don't have hopes that they did), because otherwise such machines will be doubly screwed from now on.