GPUs

AMD Radeon RX 7800XT Graphics Core “Navi 32” Spotted: Five Chiplets and 64MB of L3 Cache

AMD’s budget RDNA 3 graphics core has been spotted in a Forbes video commemorating CEO Dr. Lisa Su. The Navi 32 GPU is the younger sibling of the Navi 31 core powering the Radeon RX 7900 series cards. It will power the Radeon RX 7800, 7800XT, 7800M XT, and possibly the RX 7700 series GPUs set to launch in the coming months. It features the same MCDs (Memory Complex Dies) as Navi 31 with a 64-bit controller and 16MB of L3 “Infinity” Cache per die alongside a smaller Graphics Die (GCD).

The Navi 32 GCD should measure up to 200mm^sq, roughly 50% less than the Navi 31 GCD, which has an area of 304.35mm^sq. Subtracting the area of the two MCDs (37.5mm^sq each), you get a die ~175mm^sq sm or 33% smaller.

The fully enabled Navi 32 die features 4,096 shaders across 64 Compute Units (CUs) paired with 64MB of L3 cache and a 256-bit memory controller. Additionally, it packs 256 Texture Units and 128 Raster Output Units alongside 64 RT Cores (one per CU). The GPU has a TBP of 300W and a boost clock of almost 3GHz.

The Radeon RX 7800 XT is said to be the fastest Navi 32-based card. It may use the full-fledged Navi 32 die. The RX 7800 will be the second SKU to leverage the midrange RDNA 3 die. It will consist of 60 Compute Units (CU) or 30 Workgroup Processors (WGP) for 3,840 stream processors. The GPU will be paired with a 16GB VRAM buffer across a 256-bit bus alongside a 64MB L3 cache buffer. The TBP is said to be approximately 285W.

The Radeon RX 7800M XT is the mobile counterpart of the RX 7800 series. It should have the same core specifications as the RX 7800 with a smaller bus and cache. The Radeon RX 7800M XT nets a score of 17,842 in the 3DMark TimeSpy graphics test. This places it on par with NVIDIA’s GeForce RTX 4070 and RTX 3080 desktop graphics cards or a GeForce RTX 4080 mobile. Not bad, considering that the Radeon RX 7900 XT competes with the RTX 4070 Ti desktop GPU.

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Via: Forbes, Hoang Anh.

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