QTMMSENDMAIL performance

I hope this question doesn't require a book-length answer.

My new 820 (V5R1, 1gb. Main, lotsa DASD) has a 128K fractional T1 to an
MCI/UUNet IP address through a NetScreen firewall.  We have 7 developers and
4 support people on-line; our batch workload is light.   So why is a simple
QTMMSENDMAIL transaction so slow (up to 15 minutes) to reach its
destination?

There are many factors outside the iBox which could be causing the problem,
but sending e-mails between RoadRunner, AT&T WorldNet, and Qwest accounts
takes much less time.  So the problem is in the iBox or with MCI/UUNet (like
that would be a surprise!).

*SHRPOOL1 is our batch subsystems; *SHRPOOL2 is HTTP and TCP tasks.  No
QSYSOPR messages and we IMPL 2x/week.

I'd appreciate any suggestions to improving MSF performance...

                                                            09/10/01
13:48:32
% CPU used . . . . . . . :         .1    System ASP . . . . . . . :    111.6
G
% DB capability  . . . . :         .0    % system ASP used  . . . :
25.1812
Elapsed time . . . . . . :   00:00:01    Total aux stg  . . . . . :    111.6
G
Jobs in system . . . . . :       1290    Current unprotect used . :     1536
M
% perm addresses . . . . :       .007    Maximum unprotect  . . . :     1597
M
% temp addresses . . . . :       .012

Sys      Pool   Reserved    Max                                      Paging
Pool    Size M   Size M     Act  Pool        Subsystem   Library     Option
  1     160.33     72.42  +++++  *MACHINE                            *FIXED
  2     213.66       .28     61  *BASE                               *CALC
  3     128.00       .44     20  *SHRPOOL2                           *CALC
  4      10.00       .00      1  *SPOOL                              *CALC
  5     256.00       .00     26  *INTERACT                           *CALC
  6     256.00       .00     10  *SHRPOOL1                           *CALC