 The Model 600 used the KA66A CPU module, which contained an 83.33 MHz (12 ns cycle time) NVAX microprocessor accompanied by an external 2 MB B-cache (L2 cache) and may have one to six such modules.The NVAX was connected to the NEXMI ASIC via the NDAL bus, a 64-bit address data multiplexed system bus clocked at 27.78 MHz (36 ns cycle time).The NEXMI ASIC interfaced the NVAX to the XMI2 bus, by providing functions such as the translation of NDAL bus commands to XMI bus commands.