Transfers stops from time to time

[M4ketech]

After finally building NAS from upgrading to TrueNAS SCALE from TrueNAS Core, everything seems ok.

System details:

• Proliant ML350 G6
• CPU Intel® Xeon® Processor E5520
• 6 x 2GB ECC RAM
• 128GB SSD + 1TB HDD connected to motherboard SATA-connections.
• Bios 22.02.2018 (D22)
• 1Gbps home network
• 1x 1TB SATA HDD

Yes, there is only one 1TB SATA HDD connected to motherboard (+ 128GB SSD for boot device), this is mainly for testing and building stuff until all works.
But most of the times when transfering files, speed is around 50-100mbps, but most of the times it just stops.

This is one example, nothing happening:

And dashboard:

Also when transfering multiple items and multiple times (like copy & paste two transfer same time) both speeds go down and stops.