Running windows 8 x64 with dopus v10.5.52.0. I'm ripping personal movies to the local ssd and then moving them to the network share but I'm getting very slow network transfer speeds with dopus as compared to windows explorer. Dopus moves/copies large files (1gb plus) at some 18 MB/s while Explorer does the exact same file at 112 MB/s. Network is all gigabit on business level networking hardware. Source drive is an intel 520 ssd, network is server 2008 r2 with storage on a direct attached enterprise level raid 5 array.
If it's a non-Windows NAS (e.g. Synology or a similar brand), make sure the NAS has the latest firmware installed on it (and latest PC-side software if it uses that as well). We've seen several problems with NAS devices that were fixed by firmware updates, and where Explorer was OK but other programs like Opus were not (presumably since they mainly tested the earlier firmware only using Explorer).
It's also worth experimenting with the copy_buffer_size and copy_nonbufferio_threshold settings under Preferences / Miscellaneous / Advanced in case different settings work better with the NAS, network drivers, etc. Sometimes that can have a big effect.
Try increasing the copy_buffer_size to, say, 1MB, as a first try. Larger values may also work better, but can also slow things down. (There's no right value which is best for all hardware/driver combinations.)
Try setting copy_nonbufferio_threshold to 0, but if that doesn't work reset it back to the default value.
Also, make sure your antivirus and firewall settings are not treating Opus differently to Explorer, as that can also slow things down.
As noted, it's not a NAS. It's direct attached storage (LSI Raid card to external array) to a server 2012 hyper-v host and a server 2008r2 vm dc/file server.
Only firewall is the windows firewall and disabling av made no difference.
Disabling copy_nonbufferio_threshold definitely helps but still not even to half the speed of Windows copying the same file.
Was increasing the buffer by 1Mb and was getting improving results so tried 20Mb and get 80 MB/s. 30 and 40Mb also resulted in about 80MB/s. 15Mb was about 65MB/s so I settled on 20Mb. I have no idea the circumstances under which this setting would "slow things down" so not sure if it is advisable to leave it that high. Also, this is still not close to the 100+ MB/s I get with Windows
Love dopus but frustrated with this, hate having to go to Windows for large file copy
The buffer sizes and non-buffered I/O mode are the only real variables (that Opus itself has control over) so I can't think of anything else worth trying. The file copy loop is pretty simple; Opus reads from one file and writes to the other in a loop (reading and writing on separate threads if it makes sense to for the two devices).
One option is to use a button which copies files via the shell, as that will perform identically to Explorer.
