No. Performance depends on the HDF5 file, the application, and the platform and platform settings.
If your HDF5 file contains a simple contiguous dataset, and the application reads and writes to the entire dataset, then performance should be close to the system I/O performance.
If your HDF5 file is very complex or large or it requires a data conversion or the application is reading/writing by hyperslabs, or it is compressed (and so on), then performance may be slower than the system I/O. There are a lot of factors that can affect the performance.
If you do encounter performance problems, there may be ways to tune your application to improve performance. Please contact the The HDF Group Helpdesk if you are not able to resolve your performance problems.