News Asus Lists 4 Unannounced AMD Epyc CPUs: 8-64 Cores

[Admin]

Asus recently ushered in new firmware for the RS700A-E9-RS12V2 1U server that adds support for four Epyc processors that AMD hasn't announced yet.

Asus Lists 4 Unannounced AMD Epyc CPUs: 8-64 Cores : Read more

 

[Gillerer]

Asus also mentions the Epyc 7F32. With a 3.7 GHz base clock, it will be the fastest eight-core processor in the Epyc 7002 Series product stack. The chip has a 180W TDP, but sadly the L3 cache remains at 128MB.

If you did any analysis at all, you'd realize that:

• AMD enables cores symmetrically across all CCDs and CCXs
• every CCX on the same CPU will have the same number (either 1, 2, 3 or 4 cores)
• double that for: each CCD (=compute die) will have an even number of cores (2, 4, 6 or 8)

Then for L3 cache:

• each CCD has 32MB L3 cache, split 2×16MB between the two CCXes
• 256MB L3 cache parts therefore must have the full complement of 8 CCDs, while 128MB L3 parts can do with 4 CCDs

Conclusion:

• a 8-core EPYC CPU can only utilize 4 CCDs, because both CCXes on each have to have 1 core enabled: 1 per CCX ⇒ 2 per CCD ⇒ 8 per 4 CCD
• AMD can't produce a 256MB L3 8-core part with the current division of CCD into two CCXes