An engineering sample labeled Ryzen 9 5900X3D appeared in photos on the Chinese Chiphell forum and was detailed by Tom's Hardware on October 3, 2026. The Zen 3 processor for the AM4 socket never reached stores. The part shown has 12 cores and 24 threads, 128 MB of total L3 cache and a 105 W TDP.
What the sample shows
The retail Ryzen 9 5900X uses two chiplets, each with 32 MB of native L3, for 64 MB in total. On the Ryzen 9 5900X3D sample, only one of those chiplets received an extra 64 MB 3D V-Cache stack. The result is 96 MB of L3 on one side and 32 MB on the other, totaling 128 MB. Technical reports have not published confirmed base or boost clocks for this unit.
For comparison, the Ryzen 7 5800X3D that AMD actually sold has 8 cores, 96 MB of L3 and the same 105 W TDP. It remains the gaming reference on AM4 four years after launch. A 12-core 5900X3D would have paired that extra cache with more cores for productivity, but AMD did not sell the model.
Why it matters
The sample does not mean the Ryzen 9 5900X3D is about to launch. It is a canceled prototype that has reentered the conversation. The asymmetric layout, with 3D V-Cache on only one chiplet, is the same kind of choice AMD later repeated on newer Ryzen 9 X3D generations. In practice, the stacked cache speeds up games that depend on hot data in the CPU, while the second chiplet without the extra stack keeps higher clocks for general tasks.
Specialist tables also mention a larger prototype, a 16-core Ryzen 9 5950X3D associated with up to 192 MB of L3. That figure does not come from the photographed sample and should be read as a report of an unreleased prototype, not an official specification.
What is still unconfirmed
AMD has not publicly commented on the part. There is no price, date or sales plan. What exists is a visual record of an engineering sample and the technical reading that the company tested a 12-core chip with 3D V-Cache before concentrating AM4 gaming on the 5800X3D.
Source: Tom's Hardware, with the images originating on the Chiphell forum.
By GeekikiBot