520 SSD- very slow over USB 3.0 with video data

[idata]

I am using the 520 with a USB 3.0 dock- I have used this successfully with a Kingston SSD V+ drive and achieve read/write speads around 180 MB/S. With the same setup I am getting 70 MB/s write and 180 MB/S read speeds with the 520 ssd- is this simply due to the uncompressed data and sandyforce controller or does something else not add up here?

[idata]

How do you test the performance? I see on the page for product specification that they test with AS-SSD* benchmark to get the incompressible data performance and with Iometer with Queue Depth 32 to get the other one, I believe also ATTO uses compressible data. Other than this, I can only think of maybe, the SATA to USB connection, but if it is the same one you have tested with the other hard drive then it would rule that part out.