This read-write INTEGER sets the targeted processor clock frequency as a specific multiple of the system clock, choosing among two-to-one(1), three-to-one(2), or three-to-two(3); the description notes a possible Blackbird processor would use the 3:2 ratio. An administrator sets this to match the installed processor generation's supported clock ratio. For example, configuring three-to-two(3) for Blackbird-class processors while an older CPU expects two-to-one(1) would leave the processor clock mismatched to the interconnect.