  A new experimental setup combining X-Ray Photon Correlation Spectroscopy
(XPCS) in the hard x-ray regime and a high-pressure sample environment is
developed to monitor the pressure dependence of the internal motion of complex
systems down to the atomic scale in the multi-GPa range, from room temperature
to 600K. The high flux of coherent high energy x-rays at 4th generation
synchrotron source solves the problems caused by the absorption of the Diamond
Anvil Cells used to generate the high pressure, enabling the measurement of the
intermediate scattering function over 6 orders of magnitude in time, from
$10^{-3}$ s to $10^{3}$s. The constraints posed by the high-pressure generation
such as the preservation of the x-ray's coherence, as well as the sample,
pressure and temperature stability are discussed, and the feasibility of high
pressure XPCS is demonstrated through results obtained on metallic glasses.
