Server processors AMD Epyc 9004: BIOS update for full memory configuration
Since the presentation of the Epyc 9004 generation with up to 96 processor cores in autumn 2023, AMD has been riding a wave of success and is constantly nibbling at the market share of industry leader Intel.
In order to adequately supply the 96 cores – 50 percent more than in the previous generation – with data, AMD has provided twelve memory channels. This is how the AMD test system Titanite arrived in the c’t laboratory. But what was missing until now were servers that could show the full memory configuration: Each of the twelve channels can handle up to two registered DIMMs, 2DPC for short (DIMMs Per Channel). This not only enables the maximum memory transfer rate that can be achieved with twelve RDIMMs, but also the maximum capacity.
Updated firmware already shipped to OEM partners
And it’s precisely because of this that it has recently become suspiciously quiet and then suspiciously loud. First of all, the information about the maximum memory expansion of the Genoa CPUs was missing in presentations and prominently on the overview of AMD’s website or in the data sheet – these were only coyly hidden in footnote 7 of the linked overview (web archive link). That alone made you think, because more memory is a selling point for servers and is usually advertised quite aggressively.
There were also no Epyc 9004 servers with 24 RDIMMs in retail or in the cloud. Meanwhile, mainboard manufacturers list products with 24 RDIMMs, such as the GENOAD24QM3-2L2T/BCM from AsrockRack or the Transport CX GC68A-B8056 from Tyan. We haven’t been able to find two-socket boards for up to 12 TB of total memory yet.
Then rumors circulated that there was a hardware bug in the AMD server processor. A firmware patch should only deliver stable operation in 2-DPC mode from February, then in the second half of 2023. AMD has now confirmed to colleagues from Tomshardware.com that a correspondingly updated firmware would already be delivered to the OEM partners and that availability is expected by the end of the first quarter of 2023.
AMD has not yet responded to a request from c’t, but this is probably due to the weekend.