Thanks you therube
for trying to help me.
I use Firefox 17.01,
Sorry but I did not understand (my poor English), where to use
There is no such entry into prefs.js nor into c:\
I have tried to add a line using user.js as I done with SeaMonkey , pointing to the Ramdisk (or any other location or partition/disk) and that does not work, even if the folder has been created manually before.
Can you elaborate much in details or step by step for a noob ?