This a PET 65816 CPU card! It speeds up your PET to up to 10MHz. In fact it’s a 6502 replacement card and could be used in other 6502-based computers as well. The board uses a 65816 CPU that runs at up to 10MHz, plus a Xilinx CPLD as logic glue. It includes up to 1MByte fast RAM (run at CPU speed) plus up to 512k parallel Flash ROM (in-system programmable), that can be used as boot ROM.
Website: http://www.6502.org/users/andre/adv65/pet816/index.html