TechPowerUp noticed that AMD’s new RX 7900 GRE has physically different qualities from its larger RX 7900 series brethren. Despite the fact that all three GPUs use the same chip model, the Navi 31 package on the 7900 GRE is physically smaller than the ones on the 7900 XT and XTX.
According to an image created by TechPowerUp comparing the 7900 GRE’s new package size to the Navi 21, AD103, and original Navi 31, the die packaging of the RX 7900 GRE has been considerably revised. The package’s outer silver border has been significantly thinned and altered, giving it the appearance of a square. As a result, the Navi 31 in the GRE is smaller than the Navi 21 and smaller than Nvidia’s AD103 in the RTX 4080.
Furthermore, the RX 7900 GRE’s PCB appears to be tailor-made exclusively for AMD’s China-exclusive RDNA 3 GPU. The amount of memory packages put on the PCB is the main differentiator: just eight pads, compared to twelve pads on the RX 7900 XT and XTX.
We believe AMD physically removed the extra piping installed to drive the RX 7900 XTX’s 384-bit wide memory bus, which would also explain the altered PCB. The memory bus on the RX 7900 GRE is 256 bits wide, which is substantially narrower than the memory bus on the RX 7900 XTX. As a result, AMD probably downsized Navi 31 by deleting two MCDs worth of pipework.
What’s more, AMD’s RX 7900 GRE specifications page cites 54 billion transistors for the new chip. Meanwhile, the RX 7900 XTX and RX 7900 XT pages list 58 billion transistors. It may be a typo, but there’s certainly more going on behind the scenes than is initially evident.
Physically changing a GPU package, as AMD has done with the RX 7900 GRE, isn’t difficult, but changing the die is extremely rare – it takes a lot of money and time to pull off. AMD’s specific adjustments, as well as the rationale for the changes, are unknown. Regardless, it would be strange for AMD to go through all of this trouble for a single SKU that is only available in China.
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