Hi, I have Poser5 on an external USB2 WD 160 Gb Hard Drive and have no problems at all with it. The only things on the USB drive, are Poser5, my Poser Runtimes and ALL the Poser stuff I have purchased/downloaded over the past 4 years. I can take the drive to work and plug into my 'puter there and run Poser with minimal slowdown. Hope this helps. Robin