Speed syncing to external USB HDD became worse

[wroot]

I have tested FreeFileSync with that external drive before starting to use this tool and at that time speeds were acceptable. It was maybe 4-5 versions before. But for the last 4 months i have noticed that sync is struggling with big files. If i try to copy same file manually in File Explorer it maintains 20+ MB/s and copy takes a few seconds for 150 MB file, but in the tool it starts with 20, but quickly goes below 1 and stays like that for the most of the time, so my sync time increases a lot. Tried changing threads numbers, but it doesn't have much impact. I wonder what else i can do or check. The drive is the same and OS is the same (minus the usual monthly updates). I sync same files between two internal HDDs and it is fine.

[wroot]

Just as i have posted this i tried to sync same files again (some already synced in a few previous tries, so not exact same set) and it maintained 40-50 MBs in 2 threads. It is like it doesn't like some particular files or something and takes ages to copy them.

[wroot]

Any suggestion on that? Still having this issue syncing (mirror) to USB drive over USB3 port.

[John1234]

Hi,

Here is a simple way to test the file transfer performance between your main computer drive and your external drive to confirm that performance is as it should be or is too slow.


There is a simple speed testing tool that I have found very useful, called Fast Copy.

Set the source directory to be the same directory that you're copying files from on your source drive. Then set the destination to the external drive in a temporary folder and run the fast copy test.

https://fastcopy.jp/

[wroot]

Both File Explorer and File Copy finish my test copy of 2.6 GB of a collection of folders with big files in 1m10s or so. When i setup a mirror copy in FreeFileSync for this collection, it is done in 1m. But for some reason it takes hours to do it in my regular mirror job when copying files from the same place and speed drops from 40+ MB/s to below 1 MB most of the time. I have maybe 10 additional custom filters with *name* format. Also my sync job sync from two drives to the USB drive (one SSD, one HDD). In my test i only do sync from HDD to USB and it only has default filters. But i have same filters for other sync jobs between my SSD and HDD drives and they work ok. Just this issue when syncing to USB drive.

[wroot]

My main sync job has 80k+ files that it compare and does mirror for. Maybe it is relevant. I do sync for my browsers and mail client profiles and they have thousands of small files. But the problem with speed is mostly with big singular files (like installers and such).