Author Topic: Xbox Series X: the full specs (RDNA 2 GPU, mesh shaders, ray tracing)  (Read 1116 times)

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With power, it all begins with the Project Scarlett SoC - system on chip. The processor is fabricated on an enhanced rendition of TSMC's 7nm process, which we understand rolls up a bunch of improvements to the technology, right up to but not including the new EUV-based 7nm+. The chip itself is a 360mm2 slice of silicon (significantly smaller than we speculated), that pairs customised versions of AMD's Zen 2 CPU core with 12.155 teraflops of GPU compute power.

As expected, we're getting eight CPU cores and 16 threads, delivered via two quad-core units on the silicon, with one CPU core (or two threads) reserved for running the underlying operating system and the front-end 'shell'. Microsoft is promising a 4x improvement in both single-core and overall throughput over Xbox One X - and CPU speeds are impressive, with a peak 3.8GHz frequency. This is when SMT - or hyper-threading - is disabled. Curiously, developers can choose to run with eight physical cores at the higher clock, or all cores and threads can be enabled with a lower 3.6GHz frequency. Those frequencies are completely locked and won't adjust according to load or thermal conditions - a point Microsoft emphasised several times during our visit.


Other forward-looking features also make the cut. Again, similar to Nvidia's existing Turing architecture, mesh shaders are incorporated into RDNA 2, allowing for a potentially explosive improvement in geometric detail.

"As GPUs have gotten wider and computing performance has increased, geometry processing has become more and more bound on the fixed function vertex issue triangle setup and tessellation blocks of the GPU," reveals Goossen. "Mesh shading allows developers to completely bypass those fixed function bottlenecks by providing an optional alternative to the existing parts of the GPU pipeline. In addition to performance, mesh shading offers developers flexibility and memory savings. Mesh shading will allow game developers to increase detail in the shapes and animations of objects and render more complex scenes with no sacrifice to frame-rate."

RDNA 2 fully supports the latest DXR Tier 1.1 standard, and similar to the Turing RT core, it accelerates the creation of the so-called BVH structures required to accurately map ray traversal and intersections, tested against geometry. In short, in the same way that light 'bounces' in the real world, the hardware acceleration for ray tracing maps traversal and intersection of light at a rate of up to 380 billion intersections per second.

"Without hardware acceleration, this work could have been done in the shaders, but would have consumed over 13 TFLOPs alone," says Andrew Goossen. "For the Series X, this work is offloaded onto dedicated hardware and the shader can continue to run in parallel with full performance. In other words, Series X can effectively tap the equivalent of well over 25 TFLOPs of performance while ray tracing."


XBox Series X specs

XBox Series X specs

« Last Edit: March 16, 2020, 07:02:08 PM by JeGX »