Window
The set of instructions that is examined for simultaneous execution is called the window.Each instruction in the window must be kept in the processor,and the number of comparisons required every clock is equal to the maximum completion rate times the window size times the number of operands per instruction (typically 6 * 80 * 2), since every pending instruction must look at every completing instruction. Reference : Limitations on the Window Size and Maximum Issue Count. Computer Architecture: A Quantitative Approach, Third Edition