Some of them, if demand is high enough (and it was) AMD will just disable functional cores and sell it as a cheaper SKU; this is how all but the top of the line chips are created. There were many Phenom II X2s and X3s that could have their cores enabled without any problems. Those tri cores didn’t have unusually high failure rates anyways, I would have no qualms purchasing one. All FX 43XX, 63XX, and 83XX CPUs are the same die, same with all Intel’s i lines. You have no idea if the i5 you’re buying had a bad core or if it was just fused off so that it could fill another price bracket. There will always be bad CPUs, it’s inherent in how they’re fabricated, but Intel and AMD don’t just throw them out, that would only result in higher prices, and they’re fine as a lower end product. The Early Phenoms had much worse issues.