Thanks for the replies, folks.

I followed signals advice and adjusted changed the memory from Auto to Max. That has boosted the FPS conversion for the iPod/iPhone standard configuration from 30 FPS to about 57 FPS.

That said, for a quad core 2.6 GHz machine with 3GB of RAM, it seems slow compared to the 60 to 90 FPS figures others are quoting for slower CPUs.

Maybe the iPhone conversion is just more CPU intensive, or perhaps some other setting is still out of wac with my PC.

In any case I am much happier today with things going almost 2x as fast as the have been.

Thanks again!