The Geekworm specs are confusing. They say the board allows use of SATA hard drives, 2.5" only. I have used 2.5" with a USB to SATA adapter, and 3.5" with a powered USB to SATA adapter, and I currently have an IDE/PATA 3.5" hard drive connected with a powered USB to IDE connector. Each of these drives are limited by USB 2.0 transfer speeds, as that is what all of the Raspberry Pi models use. I have a Model B+, a Model 3 B+, and a Pi Zero Version 3.1.
In the specifications for the Geekworm product, there is only a mention of Apple Mac OSX and PC s with USB 3 data transfer to SATA 2.5" drives at USB 3 speeds. From the limited information, I can't see anything about the Pi's interface that allows the add-on board to run at USB 3 speeds. USB 2.0 max speed is 60 MBs, and USB 3.0 is 625 MBs.
I use a Themaltake Black hard drive dock to do OS imaging with Marcum Reflect on my Windows PCs. The model I have has USB 2.0 and eSATA capability for the computers that have eSATA externa interfaces; 3 of the PCs have them. USB 3.0 and eSATA transfer speeds are roughly the same. I don't have any USB 3.0 or 3.1 PCs. One of my USB to SATA adapters is USB 3.0, but it runs only 2.0 speed with the USB 2.0 interface computers I have, including the Pi units.
PCs that have only USB 2.0 provided on the motherboard can use add-on use USB 3.0 PCI cards to get 3.0 capability, but the Pi does not have expansion capability like that, unless I am totally misunderstanding something. Maybe they use the Ethernet capability, which is high speed on the Pi 3 B+.
Ted, KX4OM