Slow transfer speeds with Plugable USB 3.0 Lay Flat Docking Station.
I just received the Plugable HD dock yesterday. I get really odd transfer behavior. This is on a Win7 machine, on the USB 3.0 port.
Initially, the transfer rate is fast (~100MB/s, mega bytes per second), at least according to the instaneous speed reported by the transfer dialog box in Windows 7. But transfer speed immediately slows down, and continues to slow down the longer the transfer goes. For a 5GB video file, the average speed is about 45MB/s from beginning to end. A couple times during the transfer, the system seems to pause transferring data. The progress bar stops, even though windows reports a high transfer speed. These pauses last 10 or 15 seconds, which is what really cuts down the average transfer rate.
I think there’s a memory buffer between the dock’s USB chipset and its SATA chip. In the beginning of the transfer, that buffer is empty, and the USB chip transfers at max speed to the buffer. The SATA chip moves the data from the buffer to the hard drive on the dock, but it can’t keep up. When the memory buffer fills up, the USB chip stops requesting more data, giving the HD dock time to catch up. Maybe the firmware monitors the buffer capacity and when it reaches critical, it stops and waits for the buffer to go below a threshold level before continuing the transfer. That would explain these 10 to 15 second pauses.
gigabyte ga-ma770t-ud3 mother board. The PCIe x1 slot seems to be PCIe 2.0, but I’m unsure. The x16 video slot is 2.0, but it doesn’t list the spec for the PCIe x1 slots. Even if it’s PCIe 1.0, the transfer rates should still be capable of over 200MB/s.
Pluggable USB 3.0 lay-flat Hard Drive dock (for SATA drives).
Syba USB 3.0 PCIe card (Etron chip)
By the way, I appreciate how you host issues on your forum. I like the transparency. Every company has issues with their product.