Isn’t this how these things are always done? Same with number of cores in a CPU, the higher core and lower core come from the same fabrication process, it’s just that the lower core CPU had more faulty cores that are disabled.

Depends a lot on when its from in the product cycle, the yield at the end of production runs are usually so good that it turns into artificial product segmentation

There's an aspect of that, but the primary reason for differences between various CPUs and GPUs which have the same underlying chip is product segmentation.

Historically, there are products with high enough yield rates that it makes it irrelevant. See ATI Radeon 9500 Pro. A two byte patch in the firmware gives you an ATI Radeon 9800 Pro.

Used to be now we have chiplets. The defective chips ship as some weird OEM part usually now with parts disabled. Example: Ryzen 5 3500

I don't know what Intel is doing as I quit keeping up with them. I do miss the core unlocked boards that you'd put a 2 core cpu and maybe win the lottery on and get all 4 cores.

Yes, that's why I question the approach here.

Testing hardware is a complicated matter (you can do a PhD on the topic), and nvidia probably does a better job at it than a hacker in their basement who thinks they can upgrade their GPU for free.

On the other hand ... perhaps a few bit errors is not a problem for AI workloads ... but they could also crash your system ...

This is why, for a while, AMD was selling 3-core CPUs. They were quads with a bad core, which could sometimes be unlocked.

Sometimes people order more lower-tier chips than there are defects, and then you get fully flawless silicon with some disablement.