Memory bandwidth
"Code that runs OK-ish on that CPU averages around 1 instruction per cycle, well-optimized code around 3 instructions per cycle."<p>Is unoptimized code really that bad?<p>I thought between modern compilers and supporting 4 op/cycle with out-of-order execution, a new Kaby Lake cpu would get more than 1 cycle overall. Or are the branch delays just killing the performance? (Code is small relative to data, most of it should be in cache most of the time)