AMD EPYC Milan-X Server Processors


On November 8th, 2021, AMD held an AMD Accelerated Data Center Premiere Keynote event where they announced the upcoming EPYC Milan-X server processors. These are 7nm Zen 3 EPYC processors that are socket-compatible with existing AMD EPYC 7003 Series processors. All you will need will be a BIOS update in order to use them with existing model SP3 socket servers.

AMD EPYC Milan-X Server Processors
AMD Milan-X Details

These new processors are already in public preview for Microsoft HBv3 Azure VMs, that use the 64C/128T EPYC 7V73X SKU. The “X” at the end of the model name tell you that it is a Milan-X SKU.

Microsoft has more details here. AMD says that the large OEM server vendors (Dell, Lenovo, HPE, Supermicro, and Cisco) will have these SKUs in Q1 2022.

AMD EPYC Milan-X Server Processors

You might be wondering what is the big deal about Milan-X. Well, the answer is a huge L3 cache. Milan-X is an upgraded version of Milan using their stacked L3 cache packaging technology. The best current Milan SKUs have 256 MB of total L3 cache (which is a lot). The new Milan-X SKUs will use added L3 cache on each compute chiplet, creating a processor with a total 768 MB of L3 cache. AMD calls this AMD 3D V-Cache. The 804MB figure in the slide includes the L2 cache.

AMD claims a 50% average uplift “across targeted workloads”, which is frustratingly vague. All of that L3 cache is going to consume some power, so there will probably be some small clock speed reductions compared to regular Milan processors. They are also likely to be significantly more expensive than regular Milan SKUs.

AMD EPYC Milan-X Server Processors
AMD EPYC Roadmap

Database applications (like SQL Server) should benefit from a much larger L3 cache that reduces how often you have to access main memory which also helps reduce your overall memory latency. My guess is that OLTP workloads will see more of a benefit than DW type workloads. We won’t know for sure until we see more specifications and some benchmarks.

AMD EPYC Milan-X Server Processors
Milan-X Memory Latency

You can watch the entire keynote below.

What Else Was Announced?

In addition to Milan-X, AMD also revealed more details about the upcoming 5nm Zen 4 Genoa server processor and the 5nm Zen 4c “Bergamo” server processor families. Genoa will have up to 96 physical cores, DDR5 RAM, PCIe Gen 5.0, and CXL 1.1 support. The Genoa family is scheduled for production and launch in 2022.

Bergamo is a “cloud-optimized” variant of Zen 4 that will have up to 128 physical cores, along with all the other new features in Zen 4 Genoa. For example, it will have better power efficiency per core, which is very important to cloud providers. It is due for release in 1H 2023.

Final Words

2022 looks like it will be an exciting year for server processors! This is even more relevant because of the upcoming release of SQL Server 2022.

If you have any questions about this post, please ask me here in the comments or on Twitter. I am pretty active on Twitter as GlennAlanBerryThanks for reading!

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