For anyone reading this now and getting confused -- The Afterburner card uses an FPGA. "Programmable ASIC" is just marketing speak.
> Afterburner is a hardware accelerator card built with an FPGA, or programmable ASIC. With over a million logic cells, it can process up to 6.3 billion pixels per second. [0]
> Afterburner is a hardware accelerator card built with an FPGA, or programmable ASIC. With over a million logic cells, it can process up to 6.3 billion pixels per second. [0]
[0]: https://www.apple.com/mac-pro/