On the Silvermont microarchitecture processors, each of the instructions take around 1472 clock cycles, regardless of the operand size; and on Ivy Bridge processors RDRAND takes up to 117 clock cycles.
在Silvermont架构的处理器上，每个指令花费1472时钟周期，不论操作数大小；在Ivy Bridge架构的处理器上，花费117时钟周期。