There’s a new rumor that the pending Radeon RX 7900 XTX has 12288 stream processors distributed across two logic tiles containing SIMD components. These tiles are said to be constructed on the TSMC N5 (5 nm EUV) foundry process for the time being.
AMD’s RDNA 3 graphics chips are intended to give a 50% boost in performance/watt over current RDNA 2 graphics chips. Its Radeon RX 7900 XT graphics card is expected to have 20GB of GDDR6 memory and will compete directly with NVIDIA’s RTX 4090. Furthermore, rumors indicate that the RX 7900 XT is not the top-of-the-line RDNA 3 graphics card, implying that AMD may have something more powerful to take on NVIDIA.
There would be two Radeon RX 7900 models: the RX 7900 XTX and the RX 7900 XT. The flagship part was expected to be dubbed RX 7950 XT, however this option will be kept open for upgraded parts like the reported Navi 3X GPUs with 3D V-Cache. The Display CoreNext (DCN), Video CoreNext (VCN), and GDDR6 memory controllers will be implemented on different chiplets that will most likely be produced on TSMC N6 (6 nm). The memory interface of the “Navi 31” is 384 bit wide. The RX 7900 XTX has 24 GB of GDDR6 memory spread across a 384-bit memory interface. This memory operates at a rate of 20 Gbps (960 GB/s).
Previous speculations indicated that AMD memory arrays would include an Infinity Cache segment, with AMD’s Navi 31 silicon reportedly containing 96MB of “Next-Gen AMD Infinity Cache.” The Infinity Cache can be doubled using 3D stacking, giving the chip 192MB of Infinity Cache. If a memory controller chip on AMD’s RX 7900 XT is disabled, the chip’s tied Infinity Cache is disabled, giving the chip 80 MB of Infinity Cache (or 160 GB if mirrored via 3D stacking).
The card’s normal board power value of 420 W is the most intriguing feature of this report. Technically, this is comparable to the GeForce RTX 4090’s 450 W average graphics power value. What these rumors are based on, we do not know. Let me say it again, … rumor.
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