cohort

A 44 percent failure rate is far above any plausible hardware defect rate, so the first hypothesis is that the test or the environment is wrong rather than the hardware. The three checks that separate those, the cohort analysis that localizes a real defect, and how to run the vendor conversation.

Modules do not fail randomly at three times a published rate, so the excess has a cause and it is usually thermal or a batch. The cohort cuts that localize it, the counters that separate a dying module from a dirty connector, and the environmental cause that looks like a hardware defect.