Why does backup time vary dramatically?

Setup: My Windows XP desktop computer has two partitions, C and D. These two partitions are backed up weekly to an external (USB) Seagate “Free Agent” 500GB Drive using Paragon Backup & Recovery™, version 10.1.19.15786 (28.05.12 ) Free. The Seagate Backup Drive has two partitions named Free Agent #1 and Free Agent #2. These two partitions are the same size, (250GB) half of the 500 GB each.

Procedure: Weekly, I backup the Desktop machine’s C & D partitions to either the Fee Agent partition #1 or #2 alternating each week.

Results: It take only 121 minutes to backup to Free Agent’s #2 partition and 225 minutes to Free Agent’s #1 partition ? It creates the same 75 files having the same overall (145GB) byte count on both partitions. It just takes almost twice as much time every other week.

Concern: Is there any logical reason that this timing discrepancy might occur or should I be suspect of the backup’s validity?

Thanks for any insights you can offer in advance.

 

Do you get the same discrepancy when you use another software? For example, if you copy large blocks of data using Windows?

 

Robin,
No. I do not use any other backup software. As a matter of fact, I have used Paragon's "free" ver from a recovery CD since 2010. This discrepancy seems to have just popped up in the past three (3) months.

 

But did you do what Robin suggested? Copy the files using WIndows Explorer and see if the time difference is present. This would point to perhaps a hardware/configuration issue.

Are you measuring the time with a real clock or is it running unattended and you are relying on the time reported by the program (if it does that)?

 

Seekforever,

I'm not exactly sure what you are intending by using windows explorer to “copy the files” to determine time. In my original post, I stated that the two partitions were the same size. That determination was made using the Windows Explorer properties for those two partitions.

As to the clock and time, I used the software's reported timing when the backups were completed, and I also looked at my wrist watch and confirmed the report's accuracy.