I have the x5 2nd generation, I have the Sandisk 200GB card in it, and is working fine.
Mics: AKG c480b's, c460b's, c452eb's ( A60's, A51's ,A61's CK61, CK63, CK1, CK3 CK22, CK8), Studio Projects B3's Church Audio CA-11 ( Card and Omni)
Cables: Segue Dogstar Cables, Darktrain Silver Cables, Canare Starquad Cables
Pres: Lunatec V3, Naiant BiggerBox, Edirol UA-5, CA-9100
Recorders: Sony M10 x 2, Tascam DR-100mkii,Tascam DR-40, Edirol R-44
Playback: Fiio X5 v2, Fiio A3 v2, AKG 240MKII