They are not paying high prices because the yield is low.
They are paying high prices because it is a single source product.
Let us revisit this story...
What? Sanctions-busting sellers aren't interested in your complaints? That's a shame
www.theregister.com
China has a captive market -- Russia. And Russia, despite the plethora of electronics products in the world, is unable to access any of them. This story illustrate perfectly your example. If there is a single source of DDR5, then Apple and everyone else would paying a premium price no matter the per wafer yield. But there are many sources of DDR5, even if one source maybe slightly behind in tech node than competitors, the availability of many sources drives prices down, and any company whose DDR5 wafers have less than %50 yield will be rejected.
The yield is not defined as how many working die you get per wafer.
It is defined as how many working die you get as a percentage of the actual number of dies.
You also avoided my example. please explain why the low yielding design would be cheaper than the high yielding design, and please avoid introducing new irrelevant parameters.
Because customers do not want them, simple as that. What I presented are very relevant, not just to everyone but to the China-Russia relationship.
As a buyer, I do not care how much you want to recoup your failure rate. If there are alternatives to you, that is an edge in my favor, not yours. If your wafer have a %50 yield, that is suspicious to me. If your wafer is in the new tech node, then we can negotiate, but if your wafer is of established tech nodes same as your competitors, why should I take a chance on yours?
Look at this paragraph in that story...
Even a two percent defect rate is sub-optimal, because products made of many components can therefore experience considerable quality problems. Forty percent failure rates mean supplies are perilously close to being unfit for purpose.
A %40 failure rate mean
ALL the dies on that wafer is suspicious. It mean I do not know what I would be buying from you. A die may pass your tests but could fail mine, a %2 risk I am willing to accept, but not %40. That is what the Russian electronic products manufacturers are telling the world of Chinese semicon sold to Russia. Simplistically speaking, we can say that out of 100 washing machines, each of them have a %40 chance of failure to run. Out of 100 cars, each of them have a %40 chance of getting the Russian equivalent of the 'Check Engine' light. The average Russian would not know until he paid for his stuff.
This story perfectly illustrate the danger of having the world's semicon products so concentrated in Asia. When JPN experienced earthquakes, semicon markets reacted on the next day by raising prices. If China gain control of the SCS, the world would be similar to what Russia is going thru now.
I though that DRAM is never used in space in favour of SRAM
There is a section call 'Commercial DRAM in space'...