Silicon vendors like Intel have been saying for some time that pass/fail validation testing on high-speed I/O (HSIO) or serdes buses just doesn’t cut it anymore. Why? As the speed of HSIO buses has continued to increase, they’ve gotten much more sensitive and susceptible to signal integrity problems which can lead to failures or throughput degradations. A bus might pass a validation test in the development lab, but its operating margin relative to the eye mask might be very slight. And that’s not good.