AMD has four 256-bit execution units, which are ganged into two 512-bit execution units. Intel has only three 256-bit execution units, which are also ganged in

AMD has four 256-bit execution units, which are ganged into two 512-bit execution units. Intel has only three 256-bit execution units, which are also ganged into two 512-bit execution units, by adding an extra 256-bit unit, which stays idle in 256-bit mode. So the throughput for most register-register 512-bit operations is the same for Intel and AMD, except that AMD has a single FP64 multiplier vs. two FP64 multipliers on Intel and that the path to the L1 cache has double width on Intel (while AMD does one 512-bit load per cycle + one 512-bit store every other cycle, Intel can do two 512-bit loads from L1 + one store per cycle).