ok some success but not any understanding....

rather than linking the 2012 cube partition directly to the 2012 partition table, i link it to the main view (union of all the years' partition tables) and set a data slice to time = 2012. this processes in about 1 minute.

this is very strange because all of the other partitions are linked directly to the tables (NO data slice defined) with no performance problems. the 2012 partition table has all the same indexes as any other partition table.

if anything comes to mind please post, i'm curious what is behind this issue.