Very Slow Transfer rates ~1MiB/s

[Ross Boylan]

I am copying files from a spinning disk to an external drive connected via USB 3.

FastCopy is getting very low transfer rates, currently showing 1.4MiB/s, but as low as 0.15.

Using Explorer to copy between the same drives (while fastcopy is running) shows transfer rates 10 - 15 MB/s.

A previous run of FastCopy showed transfer rates < 0.5MiB/s during its first few hours, including after I paused some backup software.  But the next day it showed 18MiB/s.  That backup included some very large files.

Both drives are encrypted using Dell Data Protection and Encryption (DDPE) and formatted with NTFS.  External drive is cheap solid state (Seagate Expansion Drive).

There is a boatload of security and other software running.

Windows Resource Monitor seems to show FastCopy writing to multiple files at once, which surprised me.  I would have thought that would slow things down, though maybe that's only true with rotating disks.  And maybe I'm misunderstanding what the reports mean.

FastCopy 3.92 running as Admin.

Windows 10 Enterprise 1809

[SHIROUZU Hiroaki]

Your report is complex and vague, so I can't reproduce it.

Could you tell me more simple condition/environment to reproduce?

P.S.

 FastCopy doesn't issue multiple write command in the source code.

 If you want to simulate explore's copy, check "Use OS buffer for reading" and set the big number to on NTFS, on FAT, on NetDrv in OS Cache setting of I/O settings.

2021年6月8日火曜日 3:40:50 UTC+9 ross....@ucsf.edu: