In every sense except the memory, the Navi 22 is half a Navi 21. Combined, the silicon has 2,560 stream processors across 40 CUs, 40 Ray Accelerators (1 per CU), 160 TMUs, and 64 ROPs. Each of these shader engines packs 10 RDNA2 Dual Compute Units (or 20 CUs) along with the updated render backends and L1 cache. This cache is the town square for the GPU's high-speed 4 MB L2 caches and the graphics command processor, which dispatches the workload among two shader engines. A notch inside is the chip's 96-megabyte Infinity Cache, which we detail below. At the outermost level, you have the chip's 192-bit GDDR6 memory controllers, a PCI-Express 4.0 x16 host interface, and the multimedia and display engines which have been substantially updated from RDNA. The Infinity Fabric interconnect is the link that binds all the components together. Overall, the Navi 22 silicon has essentially the same component hierarchy as Navi 10. At 64, the ROP count remains the same as for the previous-generation Navi 10. AMD also redesigned the render backends of the GPU from the ground up, towards enabling features such as Variable Rate Shading (both tier 1 and tier 2). AMD claims the Ray Accelerator makes intersection performance up to ten times faster than if it were executed with compute shaders. Arranged in groups of two called Dual Compute Units, which share instruction and data caches, the RDNA2 compute unit still packs 64 stream processors (128 per Dual CU) and has been optimized for increased frequencies, new kinds of math precision, new hardware that enables the Sampler Feedback feature, and the all-important Ray Accelerator, a fixed-function hardware component that calculates up to one triangle or four box ray intersections per clock cycle.
The RDNA2 compute unit is where a bulk of the magic happens. The die talks to the outside world with a 192-bit wide GDDR6 memory interface, a PCI-Express 4.0 x16 host interface, and display I/O that's good for multiple 4K or 8K displays due to DSC. The chip measures 336 mm² and crams in 17.2 billion transistors, putting it in the same league as NVIDIA's 8 nm GA104 silicon that powers the RTX 3070. The Radeon RX 6700 XT is powered by AMD's new 7 nm Navi 22 silicon, built on the same TSMC 7 nm silicon fabrication node as the Big Navi.
The company hasn't changed its process node, but implemented a host of new technologies after having acquired experience with the node.
AMD was first to market with a 7 nm GPU more than 15 months ago, using the original RDNA architecture and Navi.
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For AMD, a lot is riding on the success of the new RDNA2 graphics architecture as it powers not just the Radeon RX 6000 series graphics cards, but also the GPU inside next-generation game consoles designed for 4K Ultra HD gaming with raytracing-a really tall engineering goal.