I play music from my notebook (JRiver). Connect to WD portable HDD 2TB via USB 3.0. My notebook specification is
There is no problem when play 24/96 or 24/192 files. But sometime, if I open lots of programs and HDD work heavily, Jriver will pause few seconds for buffering when play SACD ISO files (352.8/64).
MicroCD card has less transfer rate than USB 3.0, so I think if you want to play DSD files, you may need high transfer rate SD card.
I play my music from a netbook too connected to a HDD 3TB via USB 3.0. It is a basic eeePC and is dedicated for this purpose and has no problem with 24/192 and ISO files. I don't know about the transfer rate but a notebook/netbook has not been designed for the sole purpose of playing music I think there is a difference, assuming that FiiO has optimized the X5 to transfer music in a more efficient way.
Did someone already make a comparison between available cards with the X5?