I have a Sandisk CF 5000 (4GB) that averages 40MB/s read-write. It is plugged into a SATA-CF adapter, running in UltraDMA mode, and the system is very responsive. With an nLited XP, optimized, and EWF-enabled I can get XP to boot up in seconds from cold start. The scrollbar doesn't even get to scroll before getting to the desktop.