Elevated pressures are encountered in many metal forming processes that can alter microstructural evolution rates. Here we measure rate changes with pressure in recrystallization and grain growth in Fe through adaptation of synchrotron-compatible multi-anvil presses, originally designed for study of the mantle. Recrystallization and grain growth are monitored in situ using high-energy X-ray diffraction. Principal component analysis applied to the diffraction images is used to quantify evolution rates, with increasing pressure significantly slowing the process.