AMD Radeon RX 6800 XT Review: AMD is finally back

AMD finally has a flagship gaming card that's more than capable of matching NVIDIA's equivalent at 4K gaming.

By HardwareZone Team - 13 Dec 2020

Note: This review was first published on 19 Nov 2020.

These are exciting times for fans over at the Red Camp. After winning plaudits (including ours) for wrenching away the “best gaming CPU” from long-time competitor Intel with its Zen 3 Ryzen 5000-series processors, AMD is now pointing the crosshair at NVIDIA with its also-new Radeon 6000-series graphics cards – the RDNA 2-based RX 6800, RX 6800 XT and RX 6900 XT.

RDNA 2 marks a high point for AMD as it not only powers the new Radeon cards that the company claims can go toe to toe against NVIDIA’s impressive RTX 30-series cards in the war for the highest frame rates, but it is also the same architecture that powers the next-gen Xbox Series X and PlayStation 5 consoles. So, having cornered the console gaming segment for the next few years, AMD is now looking to gain further inroads in the PC gaming space as well.

Tell me more about RDNA 2 Architecture

The RDNA 2 architecture is really quite impressive. The TL;DR version is that in addition to a 50% per watt performance increase over the previous generation, AMD also added more compute units (CUs) and more shaders, and a cool feature known as Infinity Cache.

RDNA 2 is essentially the graphics architecture at the heart of AMD’s new graphics cards and while it may sound like a simple iteration upon the original RDNA GPUs that came before it, RDNA 2 is much more than a mere refresh. AMD’s engineers have done some significant wizardry on it that resulted in a stunning 54-percent increase in power-per-watt over the company’s previous 5000-series cards. New features include ray tracing, AI super-sampling (more on this later), and something cool called Infinity Cache.

What’s Infinity Cache?

Infinity Cache is essentially 128MB of dedicated space to help optimise memory bandwidth and latency of the 6000-series cards. What this space does is to keep all the frame buffer, z-buffer, and most recent textures cached. Basically, important visual data that would normally be stored in the GPU’s VRAM gets moved over here, freeing up that space in the VRAM for other data to speed up rendering time – much like Zen 3's unified L3 cache.

So, it’s important to note that despite the slower GDDR6 memory used on the cards, Infinity Cache allows the cards to use the memory less often, therefore reducing the strain on it and the 256-bit memory bus.

Show me the Radeon RX 6800XT

Despite the announcement of the yet-to-be released but more powerful RX 6900 XT card, the RX 6800 XT is the designated flag-bearer of the Radeon RX 6000-series family and its specifications and price-tag put it as the closest competitor to NVIDIA’s own RTX 30-series flagship – the RTX 3080. The RX 6900XT then, as you might have guessed it, is AMD’s answer to the RTX 3090 cards. AMD’s positioning of the RX 6800, on the other hand, is a little bit more unique, with its price-point putting it between NVIDIA’s RTX 3070 and RTX 3080 (I’ll be reviewing the RX 6800 separately). Anyway, the RX 6800 XT!

I did an unboxing feature of the RX 6800 XT card separately, but in summary we are looking at a reference card Made By AMD with a conventional axial cooling solution. The three fans at the bottom of the card work to pull in air to cool the 6800XT, which is then exhausted out of the side into your PC. A Radeon logo glows red when the card is powered but perhaps more interesting is the presence of USB-C port on the card – great news for VR headset users – that is also monitor compatible.

So, does the RX 6800 XT live up to the hype? Let’s find out.

Our Test Rig

We have always used an Intel-based test rig for all of our past graphics card reviews, but AMD’s Ryzen 9 5900X have proven in our review to be a fantastic choice for gamers now and so…it will also be our processor of choice for this review.

And here’s how our AMD test rig’s specification looks like:

For comparison’s sake, the obvious choice of card would be NVIDIA’s RTX 3080 Founders Edition. Both cards were tested on the same AMD-based test rig as mentioned above, with the Radeon RX 6800 XT using an unreleased beta driver (Radeon Software Adrenalin 20.45.01.12-11.6 Beta) and the GeForce RTX 3080 FE using ForceWare 457.30.

Games used for benchmarking

Here’s a list of the tool and games that I’ve chosen to benchmark both cards. The game genres were purposely varied to give us a sense of how the cards perform across a wide range of titles: shooters, racing, strategy games, etc.

3DMark (Synthetic Benchmark)
Shadow of the Tomb Raider
Total War: Three Kingdoms (Battle)
Horizon Zero Dawn
Wolfenstein: Youngblood
Deus Ex: Mankind Divided
Metro: Exodus
Tom Clancy’s The Division 2
Watch Dogs: Legion
Call of Duty: Black Ops Cold War
Gears 5
Forza Horizon 4
Control

3DMark

3DMark is a synthetic benchmark that tests graphics and computational performance at different resolutions, starting at 1080p and going all the way up to 4K. A series of two graphics test, one physics test, and then a combined test stresses your hardware in turn to assess its performance.

Here we see the RX 6800 XT matching remarkably close to the RTX 3080 in both DirectX 12-based Time Spy tests. In fact, the score difference is so minute I’d say it’s a tie. It’s the results in the Firestrike benchmarks, which tests the card’s DirectX 11 capabilities that are more interesting, as we see the RX 6800 XT outperforming the NVIDIA card convincingly. It looks like the RX 6800 XT just have better optimisations for the older API, despite modern games these days having ditched it in favour of DirectX 12.

This is a performance feat for the RT 6800 XT nonetheless, as AMD finally has a Radeon card that could make an NVIDIA’s flagship GeForce sweat. Let’s see how the card fared with real-world games benchmarks.

1080p Benchmarks (Max Settings)

I think it’s an overkill to use either flagship gaming cards to run games at 1080p and I reckon when the next-gen gaming cards (and with 1440p QHD being more widely adopted) arrive in the next couple of years, this resolution will likely become obsolete. Nevertheless, here’s how the cards fared in these games with this aged resolution.

The results do speak for themselves here; the RX 6800 XT does seem evenly matched with the RTX 3080. What’s interesting is the card performing better than the RTX 3080 even on NVIDIA-optimised games like Wolfenstein: Youngblood, Watch Dogs: Legion. It does seem like some drivers optimisation (or lack of) is in play here – note how much better the RTX 3080 performed in another NVIDIA-optimised title, Call of Duty: Black Ops Cold War instead.

1440p Benchmarks (Max Settings)

As with the 1080p benchmarks, my 1440p tests also pushed graphics settings of each game title to the highest possible.

The results pretty much mirrored the results in the 1080p benchmarks although the margins that the Radeon card gained in the earlier tests have been narrowed. In short, just like the RTX 3080, the RX 6800 XT is a great choice for 1440p gaming.

4K Benchmarks (Max Settings)

Ah…quite possibly the benchmark that we have all been waiting for. The holy grail of 4K gaming. AMD have boldly claimed that the RX 6800 XT is capable of 4K gaming at 60fps, or at least matching the RTX 3080 in performance at this resolution.

Here we see the RX 6800 XT losing some ground to the RTX 3080, with the latter besting it at Wolfenstein: Youngblood by a significant margin. It seems like the RX 6800 XT loses steam to the RTX 3080 at higher resolutions but only just. Well, in any case AMD certainly can rightfully claim that they have a card that could achieve 60fps and beyond at 4K resolution now.

Ray Tracing Benchmarks (Max Settings)

NVIDIA has been pushing ray tracing for years and their RTX 30-series has made some admirable push in performance here. The 6800 XT is AMD’s first card to enable real-time ray tracing and unfortunately it fails to match the RTX 3080’s frames per second when using ray tracing performance in the games tested above. It could not even hit 60fps at 1440p. Mind you, this is even without turning on the DLSS feature on the RTX 3080 card – so presumably performance will be even better on the NVIDIA card if turned on. I’ll get to this later in my conclusion.

Smart Memory Access

One of the key selling points of the Radeon 6000-series cards is “Smart Access Memory” or SAM. SAM is an AMD’s clever technology where they allow gamers owning both a Ryzen 5000-series CPU and a Radeon RX 6000-series GPU in the same rig to maximise system efficiencies. This is accomplished by taking advantage of the RX 6000-series Infinity Cache and allowing the CPU to directly access the graphics card’s full memory buffer, which is more than the standard 256MB that have been the norm until now. What Smart Access Memory essentially does is reduce buffering and latency, through the efficient use of the combined memory of the CPU and GPU.

SAM is great stuff for gamers, but as we can see in the above benchmark chart the margins again are negligible at best for most games. Except for Microsoft Studios’ games Gears 5 and Forza Horizon 4, where the gains are more exceptional. To be fair, even AMD have come on the record admitting that the gains with Smart Access Memory enabled, if any, are probably between five to 10-percent tops. So does the feature work? In short, yes. But it’s a fledging feature that’s only recently unlocked and perhaps requires more optimisations for gains to improve. (Spoiler: NVIDIA has also confirmed that they are looking to turn this feature on in their upcoming driver updates)

In Conclusion

I’ve said it earlier and I’ll say it again. It’s a great time for fans of AMD. At last, there’s a compelling alternative to NVIDIA’s high-end graphics cards. The Radeon RX 6800 XT is a highly competitive card that comes excruciatingly close to a performance differential to the GeForce RTX 3080, and is truly a great alternative graphics card worth considering if you are looking to game with 4K.

I say ‘alternative’, because as much as I do rate the card highly there are some other factors to consider. Ray tracing performance, for one.

Now, we must understand that ray tracing is immensely hardware intensive and without dedicated space on the GPU to offload those calculations it slows everything down performance wise. That’s why ray tracing is considered something of a holy grail in the world of video gaming.

How the RX 6000-series would handle ray tracing has always been a little mystifying. NVIDIA’s method is straightforward: build separate “RT Cores” in its RTX architecture. AMD on the other hand, rolled ray tracing into the RDNA 2’s existing Compute Units (CU) with new RT Accelerators. Each CU in turn features a single Accelerator so that every clock cycle (up to 70 of them) can be leverage for four ray tracing intersections each.

But as we can see in our 4K benchmark charts, running ray tracing on games at 4K and at 60fps is extremely difficult even for today’s best gaming GPU (i.g., the GeForce RTX 3090). Which brings me to explain why the RTX 3080 should still be the GPU of choice for hardcore gamers: namely NVIDIA’s DLSS technology.

To ‘overcome’ the challenges of ray traced gaming at 4K, NVIDIA accomplishes this with the help of its DLSS (Deep Learning Super Sampling) technology, which is in its second generation now. Powered by AI, DLSS intelligently upscale games to higher resolutions without the same performance penalty. AMD, unfortunately, has no equivalent technology ready for the RX 6800 XT launch. The company did reveal that they are already working on a super sampling solution but as of now there’s little information that we know about or when it will even be launch for the RX 6000-series.

Finally, the RX 6800 XT might have the more attractive price-tag of US$649 versus US$699 for the RTX 3080. However, it's worth arguing that by topping up an additional US$50 for the RTX 3080 you get a card that also has great 4K performance, a wider range of games that supports its ray tracing optimisations, and quite possibly the killer feature: DLSS 2.0. All of these available now and with excellent driver support. That’s pretty much a small price to pay for, don’t you think?

That said, I don’t want to take away the fantastic achievements that AMD has done with their RX 6000-series cards. The RX 6800 XT is an exceptional gaming card that still has excellent propositions to offer to gamers – you just might have to be patient with driver support. NVIDIA cannot afford to be complacent now. The same goes for Intel. And all of these can only be good for all of us.

So, chapeau AMD!

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