It looks like AMD is going ahead with its mega RDNA 3 GPU featuring several compute and memory complex dies. According to Greymon55 (a well-reputed tipster), the Navi 3x (x=4 or 5) SKU will consist of two Graphics Compute Dies (GCDs) and up to eight Memory Complex Dies (MCDs). That’s a total of eight disaggregate chiplets or dies fabbed on TSMC’s 5nm and 6nm process nodes resulting in an absolute behemoth of a graphics card.
|GPU Name||RX 7700 XT (Navi 33)||RX 7800 XT (Navi 32)||RX 7900 XT (Navi 31)||RX 7950 XT (Navi 30?)|
|Process Node||6nm||5nm + 6nm||5nm + 6nm||5nm + 6nm|
|Die Config||6nm x1||5nm x1, 6nm x4||5nm x1, 6nm x5||5nm x1, 6nm x6|
|Launch||Q4 2022||Q1 2023||Q4 2022||2023|
Each of the two GCDs will be manufactured using the N5 process, packing up to 8,192 stream processors or 16,384 overall. The MCDs, on the hand, will be a byproduct of the N6 node and pack 32MB of Infinity Cache per die via a 64-bit bus. That gives an overall last level cache of 256MB and a bus width of 512-bit. From what we know about Radeon RX 7900 XT (Navi 31), each of the memory dies will be 3D stacked with an additional cache die (3D V-Cache) for a total of 512MB of L3 cache.
The memory buffer is likely to be pegged at 32GB (GDDR6 18Gbps), making it the first consumer graphics card to feature over 30GB of memory if the RTX 4090/4090 Ti doesn’t do it first. Of course, this’ll also push the power draw well over Navi 31’s, somewhere between 450-600W. At the moment, it’s unclear what the codename for this SKU it will supposedly be called Navi 34 or 35. Furthermore, we won’t be seeing this part anytime soon. AMD is likely planning for a mid-to-late 2023 launch, probably around the same time as the RTX 4090 Ti.