i have 8 cpu. i am the only user.
create table p ( p int);
begin
for i in 1..1000000 loop
insert into p values (i);
end loop;
end;
/

set timing on
create index myindex on p(p);

Elapsed: 00:00:43.55

drop index myindex;
create index myindex on p(p) parallel(degree 4) nologging;

Elapsed: 00:00:53.19

why?