USB 3.0 all around?
The popping in/out of the memory media could be related to power. Even though this has SATA connection, reviewing some of the review posts offers if you installed just to connect the power lead(short leads, use extension), try that other slot as the mtrbd. specs offer is 3.3/5V available on top of any SATA connection, it maybe what it needs. Another review post offers it found it incompatible as it clashed with some other device. Be sure to use the driver disc. If this doesn't fix it, try another brand. I assume the USB device reader is also 3.0.