High performance computing (HPC) applications have a high requirement on storage speed and capacity. Non-volatile memory is a promising technology to replace traditional storage devices to improve HPC performance. Earlier in 2017, Intel and Micron released first NVM product -- Intel Optane SSDs. Optane is much faster and more durable than the traditional storage device. It creates a bridge to narrow the performance gap between DRAM and storage. But is the existing HPC I/O stack still suitable for new NVM devices like Intel Optane? How does HPC I/O workload perform with Intel Optane? In this paper, we analyze the performance of I/O intensive HPC applications with Optane as a block device and try to answer the above questions. We study the performance from three perspectives: (1) basic read and write bandwidth of Optane, (2) a performance comparison study between Optane and HDD, including checkpoint workload, MPI individual I/O vs. POSIX I/O, and MPI individual I/O vs. MPI collective I/O, and (3) the impact of Optane on the performance of a parallel file system, PVFS2.