The alleged die shot of the GPU powering AMD’s upcoming RX 7000 series graphics cards, based on the RDNA 3 architecture, which are launching later tonight, has leaked. While it is in no way a perfectly clear capture in glorious 4K or something, we do get a fair idea of what the Navi 31 die itself looks like.
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First, do not be confused by that “A” shaped logo on top of the image. That is the watermark of Angstronomics, who is the blogger that leaked this photo. What’s actually interesting about the die shot is the layout of the chip and its infinity cache components.
We know that AMD is moving to a chiplet-based packaging on its GPUs too. While the core will be based on an alleged 308mm2 GCD (5nm), the infinity will consist of six MCDs (6nm) each being 37.5mm2. Although prior rumors had suggested that each MCD will have 64MB of stacked cache, more recent reports suggest 16MB on each MCD for first-gen Navi 31 for a total of 96MB infinity cache.
There is reportedly also the possibility of 32MB MCDs or a total of 192MB of infinity cache on Navi 31. However, that is apparently planned for when the Navi 31 refresh RX 7×50 series comes out sometime in the future. Tonight, AMD is expected to unveil two premium SKUs, the RX 7900 XTX and the RX 7900 XT.
The chiplet design approach allows AMD to utilize a lower-cost process for stuff like the I/O or memory whereas the cutting-edge lithography can be used for the core itself.
RX 7900 XTX
The flagship RX 7900 XTX is rumored to pack 48 WGP (Work Group Processor) or 96 Compute Units (CU) for a total of 12,288 Stream Processors (SP). It will purportedly have 24GB of 20Gbps GDDR6 memory across a 384-bit wide memory bus for a bandwidth of 960GB/s. This is still not fully confirmed though and AMD may even use the slightly slower but more abundant 18Gbps memory (864GB/s bandwidth) that it is currently deploying on its RX 6×50 refresh SKUs like the RX 6950 XT, 6750XT, and 6650 XT.
RX 7900 XT
Meanwhile, the slightly cut-down RX 7900 XT will purportedly feature 40WGP or 80CU for a total of 10,752 SP. The memory subsystem is also slashed down to 20GB across a 320-bit bus. And once again, depending on the speed of the memory chips used, the bandwidth could be 800GB/s (for 20Gbps) or 720GB/s (for 18Gbps). The infinity cache will also be decreased from 96MB down to 80MB.
RX 7800 XT
Finally, we have the RX 7800 XT which will reportedly have 30WGP or 60CU which means 7,680 SP in total. This will be based on Navi 32 die instead of Navi 31. In terms of memory, the 7800 XT is expected to have 16GB of 20Gbps or 18Gbps GDDR6 for a total bandwidth of 640GB/s or 576GB/s respectively. Coming to the infinity cache, the 7800 XT will allegedly come with 64MB of the on-die cache.
Expect to know more later tonight when AMD officially takes the wraps off RDNA 3.
Source and image: Angstronomics (1) , (2) via chi11eddog (Twitter)