In cases where a store or POS comes offline for some time, the job monitor may fill up with jobs waiting to be forwarded to that destination. This should not slow down the DD Service, unless it will be restarted, as it will take time to reload all the unprocessed jobs back into DD memory. This may slow down the Job Monitor as it fills up with jobs with Error and No statutes, and it will take up more CPU load on the host where it is running.
Depending on if the location is going to be offline for long time, you have a few options to handle this, see below.
See also