Probably a knee jerk response (removing tempdb cache) that depending on how heavily your app uses tempdb will cause your app to run slower - if for no other reason, due to cache contention. Most likely the cause was:
1) concurrent update stats on different tables
2) tempdb cache too small - e.g. could have been ongoing user activity at same time
3) number of sort buffers is too high (e.g. >2500)
4) allocation of buffers between 2K, 4K, 8K & 16K pools is imbalanced
Possibly a combination of 1+3......however, in sp100 and above, I would switch to the update statistics syntax with 'statistics=hashing' clause - minimizes tempdb usage - which makes it tons faster as it doesn't have to do all the physical writes/reads for the sorting.
