Apple Afterburner is a PCIe accelerator card specifically for the 2019 Mac Pro, created to enhance Apple ProRes and ProRes RAW workflows for creative professionals by accelerating the decoding and playback of multiple streams.
Afterburner supports playback of up to 6 streams of 8K ProRes RAW or up to 23 streams of 4K ProRes RAW. It accelerates ProRes and ProRes RAW video codecs in Final Cut Pro X and QuickTime Player X, as well as supported third-party applications.
The Afterburner can be installed in any full-length slot in the 2019 Mac Pro, but it delivers maximum capability in a PCIe x16 slot. Apple Afterburner Cards ordered today from Apple's online store currently ship in five to seven business days.
For more information on the Mac Pro accelerator card, check out Apple's Afterburner FAQ.