3 ms·

That's really interesting. Not sure if this would be your area, but I'm just wondering how many "bad chips" you would have had. Like what is the failure rate

That's really interesting. Not sure if this would be your area, but I'm just wondering how many "bad chips" you would have had. Like what is the failure rate during manufacture, and what is actually happening when something goes wrong on the assembly line?

coldtea 8y ago
>* but I'm just wondering how many "bad chips" you would have had. Like what is the failure rate during manufacture* It's quite common in cpu manufacturing -- called "yield" (how many good cpus you get): "Once the front-end process has been completed, the semiconductor devices are subjected to a variety of electrical tests to determine if they function properly. The proportion of devices on the wafer found to perform properly is referred to as the yield. Manufacturers are typically secretive about their yields, but it can be as low as 30%. Process variation is one among many reasons for low yield" https://en.wikipedia.org/wiki/Semiconductor_device_fabrication https://en.wikipedia.org/wiki/Semiconductor_device_fabricati...
- deleted 8y ago
  [deleted]
soneil 8y ago
It's commonly understood (but possibly wrong?) that this is how they bin multicore processors. That it's highly likely that a quad-core and a dual-core CPU began life as identical twins, but one or two cores on the dual-core SKU didn't pass muster. If that's remotely true, and their product offer/lineup is built around the failure rates, single-core CPUs would have resulted in staggering numbers of failures, since a single defective core meant a trashcan rather than a down-SKU. (If the original supposition is true, then it's highly likely GPU, flash, ram etc work on the same principle. Anywhere you have a die with multiple repetitive units, where a die with less units still has market value, it seems like a sensible way to recoup value on what would otherwise be discards.)
- rangibaby 8y ago
  > If that's remotely true, and their product offer/lineup is built around the failure rates, single-core CPUs would have resulted in staggering numbers of failures, since a single defective core meant a trashcan rather than a down-SKU. I don't think all defective chips were DOA. A core that is stable at 1000MHz would be a Pentium 4 and another sample of the exact same chip that catches fire at 1000MHz but is stable at 500MHz would be a Celeron (etc).

coldtea 8y ago

>* but I'm just wondering how many "bad chips" you would have had. Like what is the failure rate during manufacture* It's quite common in cpu manufacturing -- called "yield" (how many good cpus you get): "Once the front-end process has been completed, the semiconductor devices are subjected to a variety of electrical tests to determine if they function properly. The proportion of devices on the wafer found to perform properly is referred to as the yield. Manufacturers are typically secretive about their yields, but it can be as low as 30%. Process variation is one among many reasons for low yield" https://en.wikipedia.org/wiki/Semiconductor_device_fabrication https://en.wikipedia.org/wiki/Semiconductor_device_fabricati...

deleted 8y ago
[deleted]

soneil 8y ago

It's commonly understood (but possibly wrong?) that this is how they bin multicore processors. That it's highly likely that a quad-core and a dual-core CPU began life as identical twins, but one or two cores on the dual-core SKU didn't pass muster. If that's remotely true, and their product offer/lineup is built around the failure rates, single-core CPUs would have resulted in staggering numbers of failures, since a single defective core meant a trashcan rather than a down-SKU. (If the original supposition is true, then it's highly likely GPU, flash, ram etc work on the same principle. Anywhere you have a die with multiple repetitive units, where a die with less units still has market value, it seems like a sensible way to recoup value on what would otherwise be discards.)

rangibaby 8y ago
> If that's remotely true, and their product offer/lineup is built around the failure rates, single-core CPUs would have resulted in staggering numbers of failures, since a single defective core meant a trashcan rather than a down-SKU. I don't think all defective chips were DOA. A core that is stable at 1000MHz would be a Pentium 4 and another sample of the exact same chip that catches fire at 1000MHz but is stable at 500MHz would be a Celeron (etc).