Please note that this post is tagged as a rumor.
AMD Navi 31 gets 384-bit bus
The most recent AMD Navi 31 spec update includes new core count, PCIe Gen5 and 384-bit memory bus.
In a response to 3DCenter.org’s Navi 3X spec update from last week, Greymon55 pointed out that the information on RDNA3 GPU memory bus is incorrect. As it is now, it appears that Navi 31 would feature 384-bit bus (not 256-bit) whereas Navi 32 would get 256-bit (not 192-bit).
That’s a major development and an important memory bandwidth boost for AMD series. Assuming that each of those cards ships with at least 18 Gbps GDDR6 memory, this would give 864 GB/s for Navi 31 alone, and that’s not even accounting for Infinity Cache. The Navi 32 memory would offer 576 GB/s bandwidth, while Navi 33 would go unchanged at 128-bit and 288 GB/s.
The Navi 31 GPU was previously rumored to feature a 256-bit memory bus and up to 32 GB of capacity. The 384-bit configuration increases the bandwidth as well as reduces the number of memory modules, which can lead to cheaper product and less demanding cooling capacity.
You should update to 128bit-256bit-384bit
— Greymon55 (@greymon55) May 18, 2022
Furthermore, based on the latest information that flagship RDNA3 GPU would be featuring 1 GCD (Graphics Compute Die) and 6 MCD (Memory Compute Dies), the MCM design of the Navi 31 could be much different from previous rumored. Rather than featuring two Compute Dies, the multi-chip design would only affect memory subsystem (L3 Cache/Infinity Cache), whereas the graphics die would be monolithic still. Twitter user @AMDGPU_ has prepared a visual demonstration of the latest information:
The specifications of the Navi 31 GPU as they stand today were included into the table below. Please note, however, that we are still weeks away from launch and there is clearly some incorrect information still floating around the web which may (and probably will) lead to confusion as we get closer to launch.
|RUMORED Specs of AMD RDNA3 GPUs|
|Fabrication Node||TSMC 5nm + 6nm||TSMC 5nm + 6nm||TSMC 6nm|
|Architecture||AMD RDNA3||AMD RDNA3||AMD RDNA3|
|GPU Package||Multi-Chip-Module (MCM)||Multi-Chip-Module (MCM)||Monolithic|
|Configuration||1x GCD + 6x MCD||1x GCD + 4x MCD||TBC|
|RDNA Workgroups (WGP)||48||32||16|
|GPU Clock||~3.0 GHz||TBC||TBC|
|Memory & Bus||24GB GDDR6 384-bit||16GB GDDR6 256-bit||8GB GDDR6 128-bit|
|Memory Bandwidth||864 GB/s (18 Gbps)||576 GB/s (18 Gbps)||288 GB/s (18 Gbps)|
|PCIe Interface||PCIe Gen5||PCIe Gen5||PCIe Gen5|
|Release||Q3/Q4 2022||Q3/Q4 2022||Q1 2023|
|Rumored SKU||Radeon RX 7900XT||Radeon RX 7700XT||Radeon RX 7600XT|
|FP32 Performance||~73 TFLOPS||TBC||TBC|
|All information based on rumors. (Updated: May 18th)|