The Netburst P4s also used a half-wide (16-bit) ALU running at 2x the clock frequency (actually by clocking on both edges, like DDR RAM), which meant ALU operat

The Netburst P4s also used a half-wide (16-bit) ALU running at 2x the clock frequency (actually by clocking on both edges, like DDR RAM), which meant ALU operations with a carry/borrow between the two halves took an extra cycle: https://www.realworldtech.com/isscc-2001/7/ https://www.realworldtech.com/isscc-2001/7/