Review Board 1.7.7 is out. It has a couple new features for admins, a series of bug fixes, and some worthwhile performance improvements that you shouldn't miss.
We did some profiling and found a couple common cases we were able to speed up considerably. The Dashboard and All Review Requests pages should be faster, as should any changes involving parent diffs.
There's also some additions in here that set things up for the upcoming PDF review extension. If you're interested in giving that a try, sign up for the beta..
Release notes are available.