http://forum.square-enix.com/ffxiv/t...beating-titan.

The above topic contains a number of players, mostly from Europe suffering from out of sync or poor latency exclusively in relation to AoE attacks, making much of the boss content extremely difficult if not impossible.

I'm suffering from this issue myself, and currently run the game via a 120mbps Virgin Media DSL connection, which is not being throttled, with a latency of about 100-110ms.