It is unknown what happened to the tablet, kreia only speculated he could have taken it. And kreias a fallible character because she has never seen the ancient sith fight at all nor met tulak.
The only time we see the ancient sith actually fighting is between naga and ludo, the only thing we have seen the ancient sith lord to is throw a brick with the force and knock his opponent out.
@ A lil side note
Vader was very powerful to a point that the ancient sith saluted him due to his powers and not greatness and built him a throne alongside them on korriban, this can be seen in empires end when palpatine communicated with the ancient sith spirits. Ajunta pall also saluted revan and im sure he admired revans power.
This is another thing which indicates to me that in terms of pure power and strength, revan and vader are prehaps on par with one another
Oh yes to any moderators who are reading this, may i request we go off topic a lil while staying on topic? It makes this discussion much more intresting