When you notice the slow down do a WRKACTJOB on the as/400 and click on the heading “CPU %” then do a shift+F4. This will show you the current jobs taking up the most CPU resources. You can then go into each job by putting a 5 in the OPT column and then enter a 10 to take a look at the log for that job to see what it’s doing. If these jobs are consistently choking the system you may want to change the run priority on these jobs. You can check the current setting by WRKACTJOB and then press F11, the PTY column has the current value. The lower the number the more CPU and resources it grabs. Word of caution here.. Be very careful when changing these values.. IF you have a runaway job that gets to much you may not be able to kill it. To change the run priority put a 2 in the opt column and press F4. This will let you set a new run priority. For your mail jobs you may want to set it at a higher value than your interactive jobs, say maybe a 30 or 40 value. If you find the system runs well with a higher setting you may want to have a programmer change the call to submit the job with the higher value permanently.