You can't say that in general. The size of the files has a big influence on the throughput.
Here are a few comments on tests I recently did:
Hardware: HP-PC 750-430nz, copying from the old external Seagate hard drive (2TB) to the Seagate Expansion Desktop (6TB).
1. test copying Photoshop Elements backup files
A PSE backup consists of many files: one file per photo (JPG, RAW) and other files like XMP and JSON.
Some of the files are very small. JSON files are typically 1KB for me.
The observed throughput (task manager) was between 45 MB/s and 100 MB/s.
2. test copying of a large file (approx. 50 GB)
Here, a throughput of 150 - 165 MB/s could be observed.
In the first test, the large disk (6TB) was the bottleneck with an active time >80%.
The creation of many small files on the 6TB disk leads to a large load on the file system (NTFS).
In the second test, the small disk (2TB) was fully utilised, 100% for a long time. I.e. the small disk was able to deliver less data
than the large disk could have swallowed.
Conclusion: Assuming a throughput of 150MB/s, it takes approx. 4 hours for 2 TB.