PG 9.3 materialized view VS Views, indexes, shared memory

Hello !

I have a huge table, 1 bilion rows, with many indexes.
I have many materialysed view (MV), subsets of this huge table, with same
kind indexes.
I have many users, querying thoses MV.
I have a storage problem, because of MV physical memory use.

I wonder :
If I replace MV with classical Views, the only indexes that will be used
will be the huge table's one. As all users will query on the same indexes,
is will always be loaded in memory, right ? This will be shared, I mean if
10 users query the same time, will it use 10*ram memory for indexes or
juste 1 time that ram ?

I terms of performances, will MV better than simple Views in my case ?

Thanks for explanation by advance

Nicolas PARIS