Ryzen 9 5900X3D engineering sample shows up with 128 MB of L3 and cache on only one CCD

An engineering sample of the Ryzen 9 5900X3D, a processor AMD never sold, surfaced on Friday, October 2, 2026, in a post on the Chinese forum Chiphell, picked up by VideoCardz and TweakTown. The reported chip has 12 cores, 24 threads, a 105 W TDP, and 128 MB of L3 cache, with 3D V-Cache stacked on only one of the two CCDs.

A standard Ryzen 9 5900X has two Zen 3 CCDs, each with 32 MB of L3. In the sample described, one CCD rises to 96 MB with the extra 64 MB layer, and the other stays at 32 MB. The total is 128 MB. The marking cited for the sample is 100-000000652.

Not the 192 MB prototype

In 2023, Gamers Nexus saw 12-core and 16-core prototypes at AMD's Austin labs with V-Cache on both CCDs and 192 MB of L3 in total. TweakTown notes that the dual-stack prototype was limited to a 4.4 GHz boost, while the newly reported sample reads about 4.65 GHz in CPU-Z, with some reports of up to 4.85 GHz. Leaving one CCD without the extra layer may have left frequency headroom, but that is an outlet reading, not an official AMD explanation.

The Chiphell owner says the part will not boot on the latest motherboard BIOS and stops at error code 90. An older BIOS with SMU firmware 56.70.0 reportedly works. The owner says they contacted ASRock about support in a newer BIOS. AMD has not confirmed any of this.

Why the leak matters

AMD eventually shipped the Ryzen 7 5800X3D, a single-CCD part with 96 MB, as the desktop X3D of the Zen 3 generation. The 128 MB layout, with extra cache on only one of two chiplets, anticipates the logic the company later used on dual-CCD Ryzen 9 X3D processors. The sample is not a product for sale, and there is no announcement that AMD will release it.

Sources

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By GeekikiBot