Flagship RDNA 4 Navi 4C GPU design leaks with complex multi-chip layout potentially incorporating up to 20 chiplets

AMD seems to have canceled the top-end RDNA 4 GPUs if reports out of various leakers are any indication. Adding to those rumors, we reported yesterday that AMD could have canned the Navi 41 and Navi 42 GPUs to ensure the development of the remaining RDNA 4 lineup and the future RDNA 5 progresses without a hitch. Tom of Moore’s Law Is Dead has now shared design details of Navi 4C, the potentially doomed flagship RDNA 4 product.

Per MLID’s latest leak, the Navi 4C takes the Multi-chip Module (MCM) design of the Navi 31 featured inside the RX 7900 XT/XTX to new levels. The picture leaked by MLID shows a design with three Active Interposer Dies (AID) which serve to interconnect chiplets and one Multimedia and I/O Die (MID) that could serve the same function as a Memory Cache Die (MCM) die currently in use inside Navi 31/32. All four (3 AID + 1 MID) dies appear to reside on top of a massive substrate. Additionally, each AID has three Shader Engine Dies (SED) stacked on top.

Furthermore, the leaker alleges that the picture only displays a portion of the overall design. For instance, there seem to be “additional” memory controller dies that the diagram has left out.

Interestingly, the design leaked by MLID mimics an already patented MCM schematic.

One thing to note here is that the leaked Navi 4C design is significanlty more complex than Navi 31/32 MCM designs with reportedly 13 to 20 chiplets in a single package. This complexity could be the reason why AMD has potentially canceled the high-end SKUs. According to one of MLID’s sources cited in yesterday’s report, the Navi 4C “wasn’t some monolithic design” and the lead team could’ve been encountering issues due to which it was “pulling in a lot of help from other teams”.

Overall, the Navi 4C which could’ve been featured inside the tentative RX 8900 XTX appears to be a big step ahead in the MCM-territory by AMD. Let’s hope Team Red manages to push past the issues and releases Navi 4C inside top-end RDNA 4 parts to rival RTX 50 Blackwell which rumors have depicted as a force to be reckoned with.

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