Industry sources told DigiTimes that TSMC is prioritizing its 28nm capacity for NVIDIA:
Since Nvidia has been unsatisfied with TSMC's 28nm process, while the company has also not refuted rumors that the company may cooperate with Samsung Electronics or Globalfoundries, TSMC, to sooth Nvidia, has put the GPU maker on its supply priority, allowing Nvidia to be able to release its 28nm GPUs on schedule in May and June.
The same situation has also happened previously with Qualcomm, which had said it would consider outsourcing orders to other wafer foundries, and successfully gained TSMC's promise for supply priority.