datatypes: text vs varchar

Hello,

    Can anybody tell us - how much 'text' datatype harder for
    database vs 'varchar(xx)' datatype? How much queries, which
    use this types differ in performance? We use only 'text'
    fields. Is 'varchar' (without specifying width) synonym
    for 'text', or not?    Thanks.


    ---
      best regards,
    Ruslan A Dautkhanov   rusland@scn.ru