well it works perfectly when daisy chained after the lacie little big disk. I thought I figured out the problem of the drop outs when I used it alone with the 512gb samsung. This morning a few minutes ago it dropped out again running off bus power alone and using the samsung 512gb. Since I jury rigged it and the connection is rock solid I am forced to think that A) bus power may not be enough for a big ssd like a 512gb type B) the samsung I have is defective. Cost me 750 so I hope this is not true C)it is fine the samsung is fine and they just don't like each other's controllers. D) an unknown. I can test this with a big 600gb intel series 320 if it is flawless that will rule out the power issue. I can also test it with the 128gb crucial for a longer period of time. I have a 256gb series 470/810 samsung. My gut feeling is that this is power related. If true then the 600gb intel will not work well. IT may mean that 256gb or 128gb ssds will be the limit for this device or that apple can patch the t-bolt port to have a bit more power.