Did you have a lot of other things in the scene? Clothing, props, other figures?

Try to do the hair animation early, before you add a lot of props, textures, etc. And if it doesn't seem to be working right, try re-starting Poser. If memory gets low, weird things happen in the Hair and Cloth Rooms.

If the hair gets too flat, you can try reducing the gravity setting.

If none of this helps, your computer may not be powerful enough to handle the sim. Using a low-res proxy instead will probably work.