OK heres an update.

I tried a quick test animation using legacy low res poser models. Creating the animation was a breez, the low poly models makes a huge difference. However, after exporting the BVH file and then loading a new scene with V4 and importing the BVH file created with the low poly models I was disappointed to see that the animation was far from perfect.

The fingers are obviously a completely different rigging set, and so it seems are the shoulders. Althought the animation ran, the fingers were all twisted, and the range of movement of V4 didnt seem to go as far as the low poly models used to create the BVH in that the limits were different. Its also seems the the IK chains are different as I noted a little weirdness in the posture of the legs (having left IK on for the test BVH set).

Although the differences could be sorted using the dope sheet and smoothing the graphs, I dont think that this post work to the BVH file is worth the time saved by using the low poly models. So its a trade-off that doesnt seem to be worthwhile at the moment.

So its back to the drawing board, or back to the stuttering scrub lines even when using hidden wireframe.... and thats on a vista 64 box with 8GB RAM, still waiting for the quad core processor, but not too hopefull that it will make enough difference to make animating V4 smooth enough to enjoy using Posers animation features.

If anyone out there is clever enough, please please give us a low poly model of the existing V4.2 so that we can make full use of the poser animation features...I know a low poly model rigged exactly the same way as our V4.2 will make all the difference.

Perhaps I am doing something wrong, so if I am beeing an ass, I would be delighted to be told so, and pointed in the right direction...

Thanks to all that have contributed to this thread...