3 ms·
Apart from the power considerations, that's very expensive. The cost of silicon grows more than linearly (I don't remember the exponent, someone help me out her
by ajb 12y ago
Apart from the power considerations, that's very expensive. The cost of silicon grows more than linearly (I don't remember the exponent, someone help me out here...) in area, because of yield issues: the larger your chip, the more likely it is that an imperfection will cause it to be worthless. With very regular designs like DRAM and flash the reduce the impact of this by redundancy, but last I heard this wasn't really considered practical for logic designs like CPUs. You can sacrifice an entire one, although apparently you have to provide for that by making a voltage island round each one, which uses some area not to mention being a nasty analog complication, although I think those are coming in anyway due to the desire to reduce base power by switching unused blocks off.
- wtallis 12y agoGPUs have for generations been designed with the intention of being able to disable defective compute units; that's why we have more than 3 models from each manufacturer. It's not done quite as much in the CPU space, but Intel does sell some server CPUs that have some cores disabled, and AMD has even sold 3-core CPUs that didn't quite pass QA as 4-core parts. There's also variability in the amount of cache memory that gets enabled on parts made from the same die. For CPUs, it's not done at any granularity finer than a whole core - nobody sells CPUs that might have one of the ALUs disabled.
- malkia 12y agoGPU have only recently being used in holding data for which losing bits may trigger a disaster (financial, banking, system, etc. data). Before that it was just for holding vertices, shaders, models, textures, etc.
- Yizahi 12y agoAlso K series CPUs (for overclockers) are chips with defective IOMMU part, small "xeon" E3 chips are Core chips with defective GPU part, and probably there is a lot of other similar binning going on with other parts.