[dannyw]

It's just an yields thing I bet; particularly given the relative lack of usage of Neural Engine. If Apple engineers realize that, disabling half the Neural Engines makes no user-visible difference and improves yields by ~1% (hence decreasing silicon costs by ~1%), that's an easy hundreds of millions in saved wafers.

[ricardobeat]

Doesn’t the fact that it’s always the first chip that gets disabled disprove that theory? If it was to improve yield you’d see the other one being disabled at least some of the time.

[fredoralive]

It probably depends on the chip yield, and the sample size of whatever survey was used for the assertion it was always the second engine disabled.

It would be reasonable to assume that if both engines work, then the second is always the one to be disabled. Therefore to have the second enabled you'd need to find one where the first engine has failed, and has no other chip killing faults. Depending on the yield TSMC gets, these could be quite rare, so you'd have to have quite a large survey to find them.

Or as other people have noted, it could be an errata meaning the second core is broken, as this isn't the only possible reason.

[WithinReason]

This would be a reasonable theory, except the neural engine is a small part of the total chip area and thus unlikely to contribute significantly to total chip yield

[marcan_42]

I know it's not the largest sample size, but I did ask twitter and nobody found one with ane1 enabled, it's always ane0.