Hewlett-Packard HP9000 Unix Workstation C-Class CPU Boards. from front to back: C110-CPU-Board - PA7200 - 110 MHz - 32 Bit - A4200-66512; C160-CPU-Board - PA8000 - 160 Mhz - 64 Bit - A4200-66517; C240-CPU-Board - PA8200 - 240 MHz - 64 Bit - A4125-66512; C360-CPU-Board - PA8500 - 360 MHz - 64 Bit - A4125-66516