sandisk ultra luxe 128 GB slow transfer rate

I have a sandisk ultraluxe 128 GB thumbdrive and the transfer rate is slow.

When copying a 400mb file the transfer rate is about 1 to 2MB/s. sometimes it even drop to 0.

The thumbdrive is connected to a USB 3.0 hub.

I have tried copying the same file to a Segate external HDD connected to the same USB 3 hub and the transfer rate is more than 50MB/s.

Can anybody tell me what went wrong?

Are you using SecureAccess to store files on the thumbdrive? The encryption process does slow down transfers.