fastest way to access db2/400 from VB

Which of the various drivers has the fastest for performance for reading
DB2/400 data from a VB app running on a PC? Most recent version of VB is
being used for the app and we are on V5R3. We used the IBM .net driver
for the app we did but have noticed some poor performance when compared
to other databases the same app uses. This app reads a single row from
DB2/400 that is all data, then reads a row with a blob from a sybase
database running on windows and does a write to an MS SQL Server
database. Time tests show the DB2/400 read taking 10 times longer than
sybase read and the MSSQL write. The DB2/400 table being read is a
logical file keyed on the same field that the SQL Select's where clause.
All servers are in the same room as the PC and on the same subnet and
same switch. The iSeries is not under any load (CPU was 10% during the
test). I did some searching and found some reference to tuning SQL on
the iSeries for each app or dumping the IBM driver in favor of a
third-party driver.