TechPowerUp has discovered that AMD's new RX 7900 GRE features some physically altered properties compared to its bigger RX 7900 series brothers. Even though all three GPUs share the exact same die model, the Navi 31 package found on the 7900 GRE is physically smaller than the one found on the 7900 XT and XTX.
According to an image TechPowerUp made comparing the 7900 GRE's new package size to Navi 21, AD103, and original Navi 31, the RX 7900 GRE's die packaging has been noticeably altered. The package's outer silver border has been thinned down considerably and re-shaped so that the package's physical dimensions look like a square. As a result, the GRE's Navi 31 is closer in size to Navi 21 and is smaller than Nvidia's AD103 which powers the RTX 4080. (The physical size of the GPU die and MCDs remains the same, the only thing that became smaller is the GPU packaging.)
Additionally, the PCB of the RX 7900 GRE is also very different and looks tailor-made specifically for AMD's China-exclusive RDNA3 GPU. The biggest differentiator is the number of memory packages installed on the PCB which amounts to just eight slots, compared to twelve slots on the RX 7900 XT and XTX.
We suspect that AMD has physically removed the additional piping that was put in place to run the RX 7900 XTX's 384-bit wide memory bus, which would also explain the re-designed PCB equipped previously mentioned. If you are not aware the RX 7900 GRE features a 256-bit wide memory bus that is significantly more narrow compared to the RX 7900 XTX. As a result, removing two MCDs worth of piping is probably how AMD shrunk Navi 31 so much.
But, altering a GPU die like AMD has done with the RX 7900 GRE is very unusual, and takes a lot of money and time to pull off. We cannot be sure of AMD's exact reasons for making these expensive changes to Navi 31, but it would be very illogical for AMD to go through all this hassle for one SKU. So we should see this same die in other GPU models down the road, possibly in the RX 7800 series and mobile GPU equivalents.
