Lag in Naxxramas / Patch 3.0.8 "imminent" (See how I used quotes?)
Unfortunately,
the optimizations we are prepared to make in order to reduce latency
and disconnections in Naxxrammas cannot be added in a hotfix. A patch
is required. I'm unable to provide a release date for the next minor
content patch including these optimizations, but I'd wager it's
imminent. (
Source)