The hair in Carrara does take a long time to calculate (slightly faster, but not much, than poser). There are a few tricks to speed it up.
If your character has only one side to the camera, you can delete the unseen hair.
The number of segments per hair can be drastically reduced.
You can place fewer, but thicker hairs on the head, this is okay for distance, but not close up renders.
You can use a prop hair and place a few animated hair strands on to it. This way you have a good head of hair, but can still animate some whispy bits.