A 12-core Ryzen 9 5900X3D with 128 MB L3 cache appears that AMD never released
An engineering sample of the AMD Ryzen 9 5900X3D has appeared in a leak with a configuration that did not reach stores: 12 cores and 128 MB L3 cache. The part adds 3D V-Cache memory to one of its two sets of cores, known as CCD.
Geeknetic already reported in 2023 on other prototypes of the 5900X3D and 5950X3D, but those had 192 MB of L3 because they incorporated stacked cache on both CCDs. The unit that has just appeared allows us to see another option that AMD tested during the development of its Ryzen X3D for AM4. There is no sales advertisement or performance data for this processor.
One CCD with 96 MB and another with 32 MB
The commercial Ryzen 9 5900X has 12 cores, 24 threads and 64 MB of L3 cache. AMD built it with two Zen 3 CCDs that provide 32 MB each. Its official file indicates frequencies of 3.7 GHz base and up to 4.8 GHz in boost mode, along with a TDP of 105 W. These figures correspond to the 5900X sold to the public; they should not be carried over to the X3D sample, whose frequencies and consumption have not been documented.
In the unit shown now, one of the CCDs retains its original 32MB and the other adds a 64MB layer of 3D V-Cache. The distribution becomes 96 and 32 MB, respectively, for a total of 128 MB of L3. The stacked layer is SRAM memory built into the processor; It does not increase the RAM installed on the computer. It is double the capacity of the conventional 5900X, although the expansion is concentrated in one of its two CCDs. The released screenshots show this organization, but they still do not allow us to evaluate how the processor would have responded in games or applications.
The distinction between total capacity and distribution per CCD matters when comparing these tests. A dual-CCD processor can achieve the same overall L3 figure using different configurations. To know what each workload gains, it would be necessary to measure, in addition to the capacity, which CCD its threads are assigned to and how the frequencies behave. Neither VideoCardz nor the owner has published a battery of tests that allows this.
AMD also tested a 192 MB 5900X3D
The new unit joins prototypes that were already known. In 2023, a 12-core Ryzen 9 5900X3D and a 16-core 5950X3D could be seen at AMD’s Austin facility. Both carried an additional layer of cache on each CCD. Its two blocks reached 96 MB of L3 separately and added up to 192 MB, a different arrangement from the 128 MB of the piece published in Chiphell.
AMD had shown the technology at Computex 2021 on a processor based on the Ryzen 9 5900X. The demo explained that each stacked layer added 64 MB to a Zen 3 CCD, which went from 32 to 96 MB. The known sample now uses that magnification on a single CCD. That presentation does not allow it to be identified as the unit that appears in Chiphell.
The AM4 product that hit the market was the Ryzen 7 5800X3D. That model has eight cores and a single CCD, with 96 MB of L3 in total. AMD later marketed the Ryzen 7 5700X3D with the same L3 capacity. Neither replicates the 12-core, dual-CCD design of the recent sample. The 5900X3D and 5950X3D versions shown in the labs They were not released to the public either..
It is advisable to separate these figures from the total cache figures that appear on some files. AMD adds L2 and L3 by presenting 100 MB for the 5800X3D, while the 96 MB mentioned here correspond exclusively to L3.
Recent BIOS stops at code 90
The owner of the sample states that The processor does not boot with the latest BIOS on your motherboard– Boot stops with error code 90. With a previous version, which uses firmware SMU 56.70.0, I would have been able to get it up and running. It also indicates that it has contacted ASRock to ask about compatibility with a newer BIOS.
This behavior comes from a single unit and the configuration described by its owner. It does not demonstrate a general problem with AM4 boards nor does it allow the failure to be attributed to a specific component. Engineering samples may require firmware other than that prepared for commercial processors, and there is no record that AMD or ASRock have promised support for this 5900X3D.
The appearance of the chip does not change AMD’s catalog. For now only the description of its owner has been seen. There is no official listing, price, release date or verifiable performance tests for this 128 MB Ryzen 9 5900X3D.
