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diff backups take the same time as full backups?

Posted: Sun Jun 29, 2025 10:25 pm
by diegoalejo15
Hi,

So I started using Terabyte to backup my Windows 10 C drive and I´m seeing that a 8 gb diff backup take 20 min, the same as the 200 gb full backup.
Is this normal?
In this case I´d prefer to always perform full backups to avoid potential issues.

Thanks

Re: diff backups take the same time as full backups?

Posted: Mon Jun 30, 2025 1:17 am
by Brian K
diegoalejo15,

When you create a Full image, pause on the Backup Options window and select "Faster Changes Only Backups". This will create two extra hash files.
#_# and #0
In addition to your .TBI.

When you create your Changes Only differential backup there is nothing extra for you to do. The hash files will be used and the time to create the backup will be markedly shorter.

Re: diff backups take the same time as full backups?

Posted: Tue Jul 01, 2025 6:58 pm
by diegoalejo15
ok, this way the diff backup took 14 min instead of 20...seems to be working as you said but I didn´t expect that if a 200 gb full backup takes 20 min an 8 gb diff backup takes 14 min anyway, not very reasonable to me.

Thanks

Re: diff backups take the same time as full backups?

Posted: Tue Jul 01, 2025 11:34 pm
by Brian K
I have a 390 GiB backup of a data partition. It took 6 minutes to create. M.2 to M.2, NVMe.
A standard differential created a few days later was only 109 MiB. Yet it took 4:20.
A metadata differential created a few minutes later only took 20 seconds. It was also 109 MiB.

I used to find a diff created with "Faster Changes Only Backups" took a third of the time of one created without that option. But if varies. Diffs save storage space even if they don't save as much time as we hope for.