Hi, I succeeded in using a 64GB Transcend SDXC in the Windows 7 Samsung Series 9, i5-3317u 13.3" ultrabook. However its almost full now... I saw somewhere the Samsung denies even that the 64GB capacity will work. Is it possible that a 128GB SDXC card will work also?
It depends on the technical design specifications of the specific 128GB SD card itself and also the SD slot. Each brand can have slightly different technical specification. Even then it can be inconclusive. The only way to actually find out is to try it yourself or wait for someone to do so.