Thank you very much.
Going to try tonight and let you know so it might also help others.

Not being very computer sentient, I was wondering if it wasn't really the fact of only having one disk. When, for example, the first encounter with alliance occurs or when I get to Shat a lot of textures and polygons(?) have to be loaded and the system is accessing 5 times the same disk in 5 different locations (I have 5 separate WoW installs).

That is another thing that was never quite clear to me, the impact in overall performance of having several/one disk and/or several/one WoW directories. If someone is willing to enlighten me I thank you in advance.

Regards,
Mortah