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I agree that a monolithic die like that wouldn't likely have really high yields. That also puzzles me though because with lower yields come more lower-grade GPUs but we haven't heard even a peep about lower-tier Radeons like the 7800, 7700, 7600 or 7500. I would've expected that there would be a lot of those ready to go from the resulting glut of imperfect Navi 31 dice.While the MCDs are tiny, there’s no usage (at present) for dies with any defects — for the 7900 cards, it’s the full die, at the required clock speeds, or nothing. So the yield is unlikely to be quite that high.
The same is also to be true of the GCD, although not to the same extent — the 7900 XTX uses a full Navi 31 and the 7900 XT only has 5 WGPs disabled (rest of the die is normal). One wafer is unlikely to yield 90% for both SKUs, as any sporting cache defects or more than 5 WGPs with problems can’t be used.
I wonder what the problem is.
Yeah, one would think... but as I said to Neeyik, lower yields should mean lots of lower-tier GPUs and we haven't seen anything. Who knows, maybe TSMC has managed to boost yields through fabrication process optimisation. After all, I would imagine that increasing yields through improvements in fabrication has to be one of TSMC's goals in their R&D departments. I don't know if this has happened for sure, I'm just postulating based on what we've seen thus far.As already mentioned, a chip of that size would not reach 90% yield, I think it is somewhere between 70-80%.