AMD
For the first time, AMD aggressively targets 4K gaming with its top-end PC graphics cards, the Radeon RX 6800, 6800 XT and 6900 XT; the company has typically stuck to the middle and lower end of the spectrum, with its previous-generation RX 5700 XT designed for 1440p play. All the new cards incorporate the RDNA 2.0 architecture that's in its GPUs for the upcoming Xbox Series X and S and PS5 consoles and directly take on the new Ampere-architecture GeForce RTX 3090, 3080 and 3070 recently launched by Nvidia. The difference - and the caveat - this go-round is that the GPUs have been optimized so that they achieve peak performance when used in conjunction with the company's new Ryzen 5000 series of desktop CPUs.
Hardware performance improvements stem partly from the higher-density on-die Infinity Cache design (all have 128MB) and enhanced design of the compute units (including a new Ray Accelerator core for each compute unit), which combine to improve the memory subsystem by reducing the latency of moving data around, increase bandwidth by up to 2.2x with a narrower path (256 bits) and deliver better energy efficiency. That also allows the processors to hit higher clock frequencies without a substantial increase in power requirements. A new Rage Mode in AMD's driver toggles one-click overclocking.
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RDNA 2's deliberately cross-platform (meaning console and PC) design allows the cards to support the same next-gen capabilities on PC and Xbox, such as ray-tracing-related programming calls for faster and improved lighting-related rendering like shadows and reflections, since both Windows and the new Xboxes essentially use the same DirectX 12 Ultimate programming interface and AMD's own FidelityFX toolset. It also enables support for Microsoft's DirectStorage programming interface, which accelerates SSD access by circumventing the CPU to improve storage-intensive game tasks like load times.
AMD has numbers showing comparable performance between the RX 6900 XT and GeForce RTX 3090 - a card significantly more expensive and power-hungry - but there's a big caveat: They're run using the cards' new Smart Access Memory. SAM basically gives the card direct access to main system memory, but only when configured in a system with one of the new Ryzen 5000 series CPUs. AMD claims that SAM combined with Rage Mode boosts frame rates by up to 13%, which means performance on Intel systems or upgraded systems won't be as good.
It will probably still be good enough given the price, power requirement and size differentials between the cards, though Nvidia's have better specs at every price - or at least at the suggested prices. We'll only know once the games begin. As usual, there are likely to be some lower-end models in the queue, unless AMD decides to leave its $400-ish RX 5700 XT-based and lower cards on the market to feed the need for inexpensive 1080p and 1440p gaming, and hopefully they'll appear in time for holiday shopping.
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