Sybase ASE Performance Difference Between a JOIN and "IN"

Question

Is there a performance difference between the ways of querying two tables in Sybase ASE, if there are 10 million records in each table:

    select top 1000 a.* from tableA a, tableB b
    where a.id = b.id

    select top 1000 * from tableA 
    where id in (select id from tableB)

Assuming that both tables have unique and non-null values for id. Intuitively: the first is faster than the second one.