Impress 3.0 very slow to load large file when run from USB flash drive

Hi
Impress 2.4 works fine but version 3.0 takes 11 mins to open a very large (107MB) presentation when I run it from my flash drive (USB2 WinXP) and it then runs unacceptably slowly. It's OK if I copy the Open office folder to my hard drive and run it from there, but version 2.4 is very slick wherever I install it. It's the same on both my desktop and my laptop.
Anyone else had this problem or found a workaround?
Bill