Check out this forum answer. This is for setting up streams and multiplexing to speed up backups
What this infers is that during a restore the opposite effect will be true based on the streams and multiplexing set up for backups.
you must review and balance need for backup completion against critical data restore.
How does the data's restore time impact DR recovery scenario's for which data.
Ex. If you are heavily multiplexing your exchange data for backup to speed up the data movement then you better test your restores to see how long it would take to get your Exchange server back up and running. Impact to companies productivity and bottom line.
In this case if Exchange function is critical to companies business productivity you better make sure the restore time is within your critical window. All Data must be evaluated by this criteria. Your backups should be configured to meet the companies DR recovery requirements. Testing with and with out multiplexing is key to determine where the correct balance is.
How much money the company loses because Exchange will take hours or days to restore because of a multiplexing value set to high will directly impact DR planning.