Slow file transfers / syncs on MacOS

[kevreeduk]

Not sure if this is "by design" (there wasn't anything in the manual about it, that's for sure!) but I've noticed particularly slow transfers when using FreeFileSync on MacOS.

Chassis - Mac Mini with 1x 1G NIC
Source location - External 8-disk RAID-6 array connected via Thunderbolt
Target - 6-disk RAID-5 array on a NAS connected via 2x10G Ethernet Connection

Transfer speed with progress window open - 500KB/s (average) and uses approx 8% CPU
Transfer speed with progress window minimised - 60MB/s (average) and uses approx 65% CPU

Not sure if there's an option I need to tick (or un-tick) to get around this yet still have the progress showing without hamstringing my transfers?

[Zenju]

These numbers don't make sense to me. When the progress dialog is minimized, FreeFileSync transforms the process to "kProcessTransformToUIElementApplication"; when restored the process is set to kProcessTransformToForegroundApplication.
I would expect the copy process to be faster while it's a foreground application. In my tests however I see no perf difference. How do other copy tools perform?

[kevreeduk]

Other copy tools have been terminal only, so no basis for comparison. We had opted for FFS because we wanted a graphical progress indicator. We were half-expecting a performance hit to account for having to draw the graphics, but not this much of a hit! I don't pretend to be a programmer, so I can't claim to understand the difference between kProcessTransformToUIElementApplication and kProcessTransformToForegroundApplication, so I defer to your wisdom on this, but I was hoping that there would be some way to not get the performance hit, whilst still maintaining the progress window in its restored form?

[Zenju]

When only 8% of the CPU are used and FreeFileSync renders the progress window with 10 FPS it cannot be the graphics rendering that is responsible for the slow speed. Are you able to consistently reproduce the speed difference when opening/minimizing the progress dialog during a large sync? This should be visible in the graphs.