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A comment on AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores. Parent comment

Re:AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores by kllrnohj on Thursday June 20, 2019 @01:21PM (#20235045)
There's 9 different independent pieces of silicon on the 64-core chip. It looks like this: https://images.anandtech.com/doci/13561/amd_rome-678_678x452... ( source https://www.anandtech.com/show/13561/amd-previews-epyc-rome-... )

Each of those smaller dies is 8 cpu cores. So 8x8 = 64. The 48-core one could either be 6 full-yield chiplets, or 8 partially defective ones with just 6 cores active. I'd guess it's 8 chiplets with 6 cores each just because that seems like it'd be more balanced, but I don't think we'll know for sure until someone de-lids a shipping one.

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Re:AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores by ip26 on Thursday June 20, 2019 @01:35PM (#20235198)
It depends on yield. If it's very high, you save money using only 6 chiplets. If it's not as great then using 8 lets you downbin the 64 core parts that were defective into the 48 core slot.

You can't do both in the same SKU because they have different performance, e.g. different amounts of L3 cache & memory bandwidth.

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