Hi folks,
Amazon had the SanDisk 200GB micro sd card on sale last week for $100, and I grabbed one without realizing it wasn't officially supported by Fiio yet. I thought I would share how it's working in my X3 II with 1.4 firmware.
I formatted it in the DAP. My computer showed pretty close to the expected capacity - a few GB less than expected (181 instead of 186), probably due to using Fat32. I loaded it up almost to capacity (about 5 GB left free).
Back in the X3, I updated the library. Took quite a while (not unexpected), and seems to max out at 19883 songs (a little over 21500 actually stored - can't remember exactly how many). However, when viewed in music folder mode, everything seems to be present and accessible. Unless some folders are empty, I think I would have noticed one of about 2000 missing files, so I'm pretty sure it's all there.
The sheer number of files and folders slows down operation - again, not unexpected, as the same thing happened when I went from a 64 to 128 GB card. Going to the SD card in music folder mode takes about 7 seconds (8 if playing), and about the same to back out of an album folder to the sd root directory. The "About X3" screen takes about 15 seconds to load.
It's not the fastest card, but I haven't noticed any glitches or hiccups while playing music. I haven't tried anything more challenging than 16/44 flac files, though. All in all, I'm willing to live with these compromises in order to have the larger capacity - YMMV. I do hope Fiio eventually adds 200GB support officially so I can shuffle through all the songs on the card.