I'm working on my game with full-hd (1080p) graphics, animations and cinematics. I'm happy how visionaire handless the graphics. Just with heaviy scenes with many animations it little gets slower. Then I re-optimize the graphics till I have the good performance.
You can always "Pre-load" the heavy animations at the beginning of the game during the Loading phase. This will significantly improve performance.
Also
I found that it is very good after an animation or character is no longer needed to unload that character and animation. This surely gives more memory but at the same time it makes loading of future animations and characters much faster.