Uninfied Memory on Jetson TK1/TX1

Dear All,

I read from CUDA 6.0 version onwards Unified memory is introduced to reduce development efforts and reducing efforts to transfer data between CPU-GPU…

Working with Jetson TK1 and documentation states physical memory is unified … does it mean i can use all memory as unified memory ?

I want to know size of unified memory available on Jetson TK1/TX1 ? How is the speed while using unified memory vs GPU memory ?