It’s time for BIG NAVI, as AMD has unveiled their new Radeon graphics cards: the $579 RX 6800, $649 RX 6800 XT and $999 RX 6900 XT. AMD claims that the cards should meet or beat Nvidia’s flagship RTX 30-series graphics cards, all the way up to the $1499 RTX 3090, often at lower price and while consuming less power. The 6000-series cards are also the first desktop AMD GPUs to support real-time ray tracing, variable rate shading and other DirectX 12 Ultimate features. All in all, it’s an exciting package for AMD fans – and would-be Nvidia users that might have become frustrated with poor RTX 30-series availability.
The performance here is what most people are looking for, so let’s start with that. In AMD’s slides, they showed the 300W RX 6800 XT trading blows with the 320W RTX 3080 at 4K, with small leads for the AMD card in Battlefield 5, Call of Duty Modern Warfare and Forza Horizon 4 and narrow losses in The Division 2, Resident Evil 3 and Wolfenstein Young Blood. Elsewhere, like in Doom Eternal, Borderlands 3, Gears 5 and Shadow of the Tomb Raider, the two cards were more or less equal. It was a similar story at 1440p, where the AMD card remained competitive in each title displayed.
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Meanwhile, the RX 6800 looks set to compete against the RTX 2080 Ti – and by extension, the RTX 3070. AMD’s marketing materials showed the 6800 beating the 2080 Ti comprehensively at 4K and 1440p, often by a 10 per cent margin or higher, although the slide notes that this is with Smart Access Memory enabled, a feature that requires a Ryzen 5000 processor (more on that later).
It was a similar story for the flagship RX 6900 XT, which is able to match or beat the RTX 3090 by a good margin despite costing $500 less – but again, that’s with Smart Access Memory enabled and the card overclocked, so it’ll be interesting to see how the cards compare at stock speeds and when using Intel processors.
So how have AMD delivered such a sharp uplift from (Little) Navi GPUs like the RX 5700 XT? One architectural change is the company’s Infinity Cache system, which is based on Ryzen’s Zen L3 cache and allows Big Navi’s 256-bit memory bus to attain 2.17x the bandwidth of a traditional 384-bit memory bus while using less power. Graphics card clock frequencies are also up 30 per cent, while using the same 7nm process. Combined with efficiency improvements to the compute units themselves – AMD noted ‘pervasive fine-grain clock gating, aggressive pipeline rebalancing and redesigned data paths’ – and you have a significantly more performant GPU.
| RX 6000 Specs | CUs | Boost Clock | VRAM | Infinity Cache | TDP | Price |
|---|---|---|---|---|---|---|
| RX 6900 XT | 80 | 2250MHz | 16GB GDDR6 | 128MB | 300W | $999 |
| RX 6800 XT | 72 | 2250MHz | 16GB GDDR6 | 128MB | 300W | $649 |
| RX 6800 | 60 | 2105MHz | 16GB GDDR6 | 128MB | 250W | $579 |
Let’s take a look at the specs, starting with the RX 6800 XT. This card uses 72 CUs (compute units), a boost clock of 2250MHz, a 128MB Infinity Cache and 16GB of GDDR6 memory. The 6800XT also manages this at a lower power envelope than the RTX 3080, 300W vs 320W. Meanwhile, the RX 6800 has 60 CUs, a 2105MHz boost clock but the same Infinity Cache and VRAM allocation; its TDP is 250W. The RX 6900 XT was a well-timed ‘one more thing’ at the end of the show, and is a fully-enabled 80 CU version of the RX 6800 XT with the same clock speeds, memory configuration and a 300W TDP.
While the hardware on show was impressive, it’s helped by two performance-boosting features. Rage Mode is a one-click GPU overclocking button that should be able to safely eke the most performance out of your graphics card, while a feature called AMD Smart Access Memory which allows Ryzen 5000 processors easy access to Radeon 6000 GPU memory to boost frame-rates further. When this is enabled in the BIOS and combined with Rage Mode, AMD showed game performance increase from two to 13 per cent – although a single-digit boost was more commonly featured in AMD’s marketing materials. As well as frame-rate boosting measures, AMD has updated their Anti Lag and Radeon Boost to reduce input lag in GPU-bound scenarios.
As we mentioned above, the RX 6000 series will be the first AMD GPUs to support DXR ray tracing and other DirectX 12 Ultimate features, but we don’t have a good idea of ray tracing performance on the new cards, so hopefully this will be detailed soon. AMD also hasn’t announced a true competitor to Nvidia’s DLSS feature, which boosts frame-rates significantly in supported games to help offset that RT cost, so we’ll have to see if anything like that emerges later on.
But what about ray tracing performance? ?
— Alexander Battaglia (@Dachsjaeger) October 28, 2020
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We’ll have to do our own testing with Radeon 6000 to validate these claims, but on balance this was a hugely impressive reveal for a company that wasn’t able to touch Nvidia’s highest-tier cards with their last-gen offerings. The RX 6800 and 6800 XT are launching on November 18th, with the RX 6900 XT following on December 8th, so we don’t have too long to wait!
