The AMD EPYC 9004 series, codenamed “Genoa” is nothing short of a game-changer. We use that often in the industry, but this is not a 15-25% generational improvement. The new AMD EPYC Genoa changes the very foundation of what it means to be a server. This is a 50-60% (or more) per-socket improvement, meaning we get a 3:2 or 2:1 consolidation just from a generation ago. If you are coming from 3-5 year-old Xeon Scalable (1st and 2nd Gen) servers to EPYC, the consolidation potential is even more immense, more like 4:1. This new series is about much more than just additional cores or a few new features. AMD EPYC Genoa is a game-changer, and we are going to go in-depth as to why in this article.
This is going to be perhaps the longest piece on STH this year. We are going to have a ton in here, and as I am writing this a week before launch, we have had to cut the scope from this piece just due to time constraints. With that, let us get to it.
AMD EPYC 9004 Genoa: The Video
This is a (very) long article. We also have a video, and this may be one of the few pieces we do that will be faster to get a summary while watching, rather than reading. Here is the video:
We have a lot more detail in this article, but if you want to put that one on as a podcast (you can even speed it up) for later, feel free to get an easy overview. As always, we suggest opening this video in its own window, tab, or app for a better viewing experience.
AMD EPYC Genoa Market Context: Today’s Market
AMD is launching the Genoa part at a somewhat strange time. Intel still has its Ice Lake and Cooper Lake generation Xeon parts as part of its 3rd Generation Intel Xeon Scalable family. That means, Intel has chips with up to 28 cores and 6 channels of DDR4 that can scale to 4-8 sockets (and down to one) and 40 cores and 8 channels of DDR4 for 2 socket applications. The full instruction set is mostly common, but a few examples, such as bfloat16 support are not identical between the two.
If you took a top-end dual-socket Ice lake server with 2x 40 core Ice Lake Xeon CPUs, and a top-end 4-socket server with 4x 28 core CPUs, you would get 192 cores total, or the same as a top-end dual-socket Genoa server. The aggregate memory bandwidth would be in a similar ballpark as well. In this review, Genoa may feel like an asymmetric advancement, and that is because it is. Intel will have its response in two months but it will not compete directly on a core-for-core basis with the 84 and 96 core Genoa. Intel will instead focus on the 16-64 core mainstream market when Sapphire Rapids arrives in 2023.
The chips themselves are absolutely gigantic, as are the resources they offer. Here is lscpu output of a dual AMD EPYC 9654 96-core processor system with 192 cores, 384 threads, and 768MB of combined L3 cache.
Our technical readers in the screenshot above will also notice that there is a huge number of new instructions including AVX-512 and AI-focused instructions including VNNI from Ice Lake Xeons to bfloat16 support from Cooper Lake Xeons.
AMD’s approach is simple. It is using the same basic Zen4 CCD die that it uses in its desktop Ryzen 7000 series products and combines more of them along with a much larger and more capable I/O die into a package. New for this generation is that AMD is using up to 12 instead of up to 8 of these CCDs as it did in its EPYC 7002 (Rome) and EPYC 7003 Milan generations.
Intel’s focus, knowing that AMD will have a roughly 50% core count advantage at the top end will be to battle it out in the heart of the market that buys lower core count SKUs and to utilize accelerators to give performance gains well beyond what cores alone can provide.
AMD EPYC 9004 CPUs are the start of a very different environment in the server world. While they are relatively huge, they are not going to be AMD’s highest performing on a per-core basis nor even have AMD’s highest core counts in this cycle. Genoa is simply AMD’s mainstream part.
AMD EPYC Genoa Market Context: There is More!
Perhaps the biggest difference between this launch, and some of the previous launches, comes down to positioning. AMD now has sufficient scale to go beyond a single design for the entire market, scaling cores, frequency, and TDP. Instead, AMD now will have segment-specific solutions for some of its larger segments.
The first of these solutions is the new AMD EPYC Bergamo. This will use the same AMD Socket SP5 as Genoa, but with a focus on maximizing core counts for cloud workloads. AMD will reduce cache sizes to fit more cores, but otherwise, this is going to be AMD’s high core count solution at up to 128 cores per socket. Genoa’s headline is only 96 cores. We will be excited for a 50% generational increase in core counts in this article, but Bergamo is another 33% increase from the 96-core mark and is slated for 1H 2023. This is AMD’s answer to the threat of Arm server CPUs.
Genoa-X will break the 1GB/ socket of L3 cache barrier. With standard Genoa, we get up to 384MB of L3 cache per socket or 768MB of L3 cache per 2P server. With Milan-X, we had 64 cores and up to 768MB of L3 cache per socket. We expect AMD to offer over 2GB of L3 cache in a dual-socket server in 2023. Genoa-X will be targeted at applications, such as those in the HPC space, where adding 3D V-cache increases data locality to the point that less power is wasted moving data. Genoa-X is for HPC and we hope to see other verticals serviced with parts like frequency optimized, high-cache parts for databases, but AMD has not talked about that to date.
The new SP5 socket servers are so large, that they are simply too big for many applications.
The new AMD EPYC Siena platform will be designed to go into more edge devices. That is a hot space and we already have seen companies like Ampere with its Arm-based processors start to show proofs-of-concept for the intelligent edge.
AMD Instinct MI300 is perhaps the other HPC part. This will combine x86 and GPU IP into packages that also have high-speed memory onboard. NVIDIA will have Grace Arm CPU and NVIDIA GPU modules and Intel with Falcon Shores XPUs. This is an industry trend that we expect in the supercomputer and HPC spaces.
The bottom line here is that the AMD EPYC Genoa launch today is different than the Naples, Rome, and Milan launches previously. Genoa is not expected to serve the entire market with HPC, cloud, and edge markets using different AMD chips later in 2023.
With that, let us get to how Genoa is made.