Please check the Job log of the completed backup job (recent one) and compare it with the older job lkog which was taking less time. This will give you the data like which resource is taking longer time to backup now. Ones we know the data we can isolate further.
Has anything changed in your setup? Has the size of the backup increased?
Review the job log details for one of the jobs that is taking longer time and compare it with the sae job when it was running overnight.
What you need to specifically look for is the job rate, bytes backed up and time take for every resource. Once you have pin pointed what resource/s is slowing the job down, it would be easier to troubleshoot.
So after extensive research the backup size is just about the same, there is no real gap here. The job rate is the difference maker. On a good backup the job rate is at 589.00 MB/min on the bad ones its at about 230.00 MB/min. This is for a daily differential. I have noticed there are system states running. Should that be running?
Please refer to the article
set the exclusions for backup exec directories and services
than retry with the job, another thing you do is turn of real time scanner and than run a backup job to confirm its not antivirus causing the same issue.
try the below procedure if you are using ESET NOD32 V4...
ESET NOD32 ANTIVIRUS V4