AMD unveils its Radeon RX 6900 XT, RX 6800 XT and...

During a long-planned event, which took place today at 5:00 p.m., AMD presented Big Navi graphics cards, engraved in 7 nm and equipped with a Navi 21 GPU. As with the Ryzen 5000, the range has only a few products, three to be precise; namely the RX 6900 XT, RX 6800 XT and RX 6800. You will have understood it with the numbers, the company directed by Lisa Su directly attacks the high-end segment and the game in 4K.

As for the prices, they are 999 dollars for the RX 6900 XT, 649 dollars for the RX 6800 XT and 579 dollars for the RX 6800. In gross conversion, this gives respectively 850, 552 and 493 euros. For the XT variants, AMD opts for a more attractive pricing policy than NVIDIA: the RX 6800 XT, positioned opposite the RTX 3080, costs $ 50 less than its rival, posted at $ 700; the difference is $ 500 between the RX 6900 XT and the RTX 3090, which sells for $ 1,500; however, the RX 6800 costs more than the RTX 3070, which trades in $ 499.

Architecture RDNA 2

We will only briefly come back to the RDNA 2 GPU architecture, presented in a previous update. In summary, it mainly introduces DXR hardware ray tracing and Variable Rate Shading, a process that AMD says “Dynamically reduces the shading rate on different portions of an image when these do not require a high level of detail, for superior performance without noticeable change in the final image quality”.

However, the conference was an opportunity to lift the veil on two new technologies.

Infinity Cache et AMD Smart Access Memory

The first is the mysterious Infinity Cache discovered a few days ago. The company has remained rather elusive. The main idea is to reduce memory traffic thanks to an L3, or even L4, cache capable of containing the entire frame buffer. AMD explains the process as follows: “The Infinity Cache is a high-performance, next-level data cache perfect for 4K and 1440p gaming with the highest level of detail. 128 MB of on-die cache drastically reduce latency and energy consumption and offer the best in-game performance compared to traditional architectures ”. In the case of the RX 6800 XT, the company claims that this Infinity Cache reduces power consumption by 10% while increasing effective bandwidth by 117%.

The other feature highlighted by AMD is Smart Access Memory: for users with a Ryzen 5000 processor, a B550 or X570 motherboard and a Radeon RX 6000, “The AMD Ryzen processor benefits from greater access to GDDR6 graphics memory, thereby speeding up CPU processing. The result is a 13% performance boost on an AMD Radeon RX 6800 XT graphics card in Forza Horizon 4 in 4K ”.

Now we come to the characteristics of the three cards. A summary table is available at the end of the page, as well as a replay of the conference.

Radeon RX 6800 XT

Let’s start with the model that will surely enjoy the favor of customers the most: the RX 6800 XT. It has 128 ROPS, 72 RA (Ray Accelerators) and 72 computing units, or 4,608 flow processors in total. This RX 6800 XT benefits from 16 GB of GDDR6 memory at a speed of 16 Gbit / s on a 256-bit bus; to this is added a 128 MB Infinity Cache. The bandwidth is 512 GB / s.

Regarding frequencies, the maximum frequency is 2.25 GHz. This card offers a maximum computing power of 20.7 TFLOPS and a texture fill rate of 648 GT / s; For comparison, the RX 5700 XT offers a power of 9.75 TFLOPS and a texture fill rate of 304.8 GT / s. Finally, the TBP (Total Board Power) is 300 W. AMD recommends a power supply of at least 750 W for the entire configuration. Power is supplied via two 8-pin cables.

Now, in terms of performance, as leaks suggested, this Radeon RX 6800 XT is, according to AMD tests (without ray tracing), very close to the RTX 3080; sometimes in front, sometimes behind. However, AMD’s solution also claims a lower price, more memory and a slightly lower TBP.

Radeon RX 6800

Now let’s move on to the RX 6800; Concretely, this RX 6800 is to the RX 6800 XT what the RX 5700 was to the RTX 5700 XT: two cards that share the same GPU (in this case, Navi 10), but a first one that is a little less well endowed than the second, both in hearts and in frequency.

In the case of the RX 6800, we thus find a Navi 21 GPU, but only 60 RA, 60 calculation units, or 3,840 stream processors, and 96 ROPS. The Boost frequency is also a little behind, with 2 105 MHz. However, it retains 16 GB of GDDR6 memory and 128 MB of Infinity Cache; the bandwidth is therefore still 512 GB / s. The single precision computing power of the RX 6800 is 16.17 TFLOPS; its texture fill rate of 505.2 GT / s. Its TBP drops to 250 W; powering it still requires two eight-pin connectors.

A promising card in short, very well endowed with GDDR6 memory for the price, and that we can not wait to see the NVIDIA RTX 3070 in games. In any case, according to figures communicated by AMD, this RX 6800 is ahead of the RTX 2080 Ti by around 10%; a domination that the RTX 3070 can also boast of. However, in exchange for an additional 80 dollars, the RX 6800 grants twice the VRAM, better bandwidth and performance. a priori higher. In short, in this segment, there is a risk that there will be fierce competition between the two competitors.

Radeon RX 6900 XT

We saved the best for last, with the RX 6900 XT as a final touch; in other words a Big Navi exploited in all its power.

However, on paper, the Radeon RX 6900 XT is not that far removed from the Radeon RX 6800 XT; it mobilizes 80 computing units and promises a Boost frequency of 2 105 MHz. For memory, it is housed in the same boat as its little sisters and must therefore be satisfied with 16 GB of GDDR6 memory, on a 256-bit bus, at 16 Gbit / s, combined with a 128 MB Infinity Cache, for 512 GB / s bandwidth. Its TBP is at 300 W, like the RX 6800 XT. Its single-precision computing power is 23.04 TFLOPS and its texture fill rate peaks at 720 GT / s.

Enough to challenge the RTX 3090? Yes, according to AMD. As with the RX 6800 XT versus the RTX 3080, the results are pretty tight; but then again, just remember that $ 500 separates the RTX 3090 from the RX 6900 XT to designate a winner.

However, note that for the RX 6800 and RX 6900 XT benchmarks, the Rage Mode and Smart Access Memory features are enabled; this mention is not present on the slides of the RX 6800 XT.

Conclusion

You will agree, these Radeon 6000s are a lot like what the first Ryzen caused in the processor market: a real upheaval. We must remain cautious and wait for neutral tests to form a final opinion, but the Navi 21 GPU, available in three cards, looks very promising. If in terms of calculations, the RTX 3000 from NVIDIA seem superior, the Navi 21 cards can claim their 16 GB of GDDR6 memory, their consumption content and their attractive price.

However, the fact that AMD did not report any performance figures with ray tracing enabled is a bit surprising, not to say concerning. NVIDIA has taken the lead in this area; in addition to a catalog of titles that grows over the months, saving technologies such as DLSS bring real added value. Well, we’re not really worried about AMD, which of course has something to react to with similar technology, the Super Res integrated into FidelityFX: 35 compatible games are planned, 25 are already available, among which Borderlands 3, Death Stranding, Gears 5, Ghost Recon Breakpoint…

Finally, a final determining criterion will quite simply be availability. For NVIDIA’s RTX 3000s, the situation is very tense; if AMD manages to guarantee a sufficient supply, it is not excluded that customers will naturally go for a card they can get, in other words an RX 6000.

Answer in the coming weeks, since the Radeon RX 6800 and RX 6800 XT will arrive on November 18, 2020, and the RX 6900 XT, on December 8, 2020.

Summary table