PICMG 1.3 evolved from the older standard PICMG 1.0. However, PICMG 1.3 uses PCIexpress as the interface and not PCI or ISA. PCI is still available as an option. CPU boards with PCIMG 1.3 are available as full and half size boards. The dimensions of a PICMG 1.3 half size CPU board are 168 x 126 mm.