(1) The pane showing cache devices is too narrow on my computer.
(2) After removing two usbs device - first from Eboostr, then from the computer (although I think that in the case of one of the devices I forgot to remove it from Eboostr first) - I could not, upon reconnecting the device, select it as a cache in Eboostr, even though the device was accessible to Windows (XP SP3). Uninstallation and then reinstallation fixed the problem.
(3) After I had solved the above problem (=2), I had problems rebuilding the cache on both my usb device and my system memory. The system memory is presently only 66& full, and the usb (flash) device, 1%.
As to the 'hidden ram caching': that's a very good idea indeed, and it seems to work. Well done!
Finally: an ability to save configuration between installs, and to automatically exlude certain file types (.bak, .tmp, .msi, et cetera) would be good.