Write speed on Thunderbolt 3 Shuttle is very slow

I am running a Lenovo P72 with the latest versions of h/w drivers for everything that is on board this laptop. It’s Windows 10 Pro.

I am also running the latest version of the G-Technology device driver and software.

I have enabled Device Cache writes in Window’s Device Manager for the Shuttle.

Running in RAID 5 mode - the fastest sustained writes I have seen so far is about 100MB/Sec - I expected about 500MB/Sec write speeds.

100 MB/sec is way too slow for this box. Can somebody point me to some parameters to set? Thank you.

Sorry - I made a big mistake. I was copying data from an external USB hard-disk to the Shuttle. As it turns out - the USB disk was the slow one. I have tested copying data from my internal SSD to the Shuttle - and the write speed is about 500MB/sec - as I expected.