AMD Radeon RX 6800 XT and RX 6800 Review: Big Navi Delivers
Our First Look At Radeon RX 6000 Series Performance
A long time ago in a galaxy much like this one, humanoid beings first became aware of the phenomenon known only as “Big Navi”. As elusive as the similarly-named but only tangentially-related Bigfoot from Earth’s not-quite-ancient history, we now have much more than grainy handheld camera footage or VideoCardz leaks.
Yes, the wait is finally over. Take a deep breath. Shout it from the rooftops:
BIG NAVI IS HERE!
That feels better. But scream therapy alone will not answer the questions we had about performance with the new Radeon RX 6800 Series cards in independent testing, though AMD did provide a fairly comprehensive preview of performance ahead of this launch. Will there be any surprises? Maybe, but without spoiling too much I think that the only thing Team Red fans will have to worry about today is availability, and not performance.
We won’t be diving too deeply into architecture here, but what AMD has accomplished is certainly worth at least a quick look. We knew that increasing the Compute Unit (CU) count would offer a huge boost in performance even without significant architectural improvements, as the previous Radeon RX 5700 XT offered great performance with just 40 CUs. But the Radeon Technology Group was obviously not content to simply up the CU count – which now tops out at 80 with the RX 6900XT.
AMD RDNA 2 architecture introduces significant architecture advancements from RDNA architecture in the form of an enhanced compute unit, new visual pipeline featuring Ray Accelerators, and all new AMD Infinity Cache. The focus for AMD RDNA 2 architecture was to deliver breakthrough speeds with amazing power efficiency. With up to 1.54x higher performance-per-watt and 1.3x higher frequency at same per-CU power, RDNA 2 architecture is designed for the next generation of efficient high-performance gaming.
The approach that AMD has taken is quite interesting, and quite effective. With RDNA 2 we have a mix of improved performance-per-watt, very high clock speeds, and a unique graphics memory cache implementation – known as Infinity Cache – which is a brilliantly realized solution to the problem of memory bandwidth.
The goal to make AMD RDNA 2 a highly power efficient architecture resulted in the creation of the AMD Infinity Cache – a cache level alters the way data is delivered in GPUs. This global cache allows fast data access and acts as a massive bandwidth amplifier, enabling high performance bandwidth with superb power efficiency.
A highly optimized on-die cache results in frame data delivered with much lower energy per bit. With 128MB of AMD Infinity Cache, up to 3.25x effective bandwidth of 256-bit of GDDR6 is achieved, and when adding power to the equation, up to 2.4x more effective bandwidth/watt vs 256-bit GDDR6 is achieved.
Without a doubt the concept of a bigger, higher-powered version of the same graphics found in the latest consoles is an exciting one for PC gamers, but the results will speak for themselves. Has AMD suddenly made the gaming landscape a highly competitive one, trading blows with even NVIDIA’s fastest current GPUs? We will move on to the some benchmark results shortly, but first let’s take a look at the Radeon RX 6000 Series lineup:
|AMD Radeon RX 6900 XT||AMD Radeon RX 6800 XT||AMD Radeon RX 6800|
|Memory||16GB GDDR6||16GB GDDR6||16GB GDDR6|
|Memory Interface||256 bit||256 bit||256 bit|
|Game Clock||2015 MHz||2015 MHz||1815 MHz|
|Boost Clock||Up to 2250 MHz||Up to 2250 MHz||Up to 2105 MHz|
|Infinity Cache||128 MB||128 MB||128 MB|
|Total Board Power||300W||300W||250W|
|Launch Date (Expected)||12/8/2020||11/18/2020||11/18/2020|
Of course availability will be a big part of the story with any major hardware launch this year, and we can only hope that AMD has built up supply for those eager for an upgrade.
AMD’s Radeon RX 6800 and RX 6800 XT Reference Cards
Before we get underway here’s a quick look at AMD’s reference design for both cards, and as you can see the only difference is the thickness of each card. The RX 6800 is a standard dual-slot width card, while the RX 6800 XT is a 2.5 slot card. Both cards are 10.5 inches (267 mm) long.
These triple-fan coolers have a premium look and feel, finished nicely with an aluminum backplate. The cards are also on the dense side – particularly the RX 6800 XT, which weighs approximately 3 lbs 5 oz (heavier than the RTX 3080 FE).
An interesting note on the design is the lack of any vents on the I/O bracket, meaning all of the warm air will be exhausted into the case. As with the RTX 3080 Founders Edition design good case airflow will be required for best performance – though NVIDIA’s design does exhaust some air from the back of the card.
As to power, both cards require two standard 8-pin PCIe connectors, with AMD recommending a 650W power supply for the RX 6800, and a 750W power supply for the RX 6800 XT.
As I said last year with the RX 5700 Series launch review, the results to follow speak for themselves so I won’t add much in the way of commentary. As you scroll through the charts bear in mind the pricing with these Radeon cards, with the RX 6800 XT $50 lower than NVIDIA’s RTX 3080 ($649 vs. $699) and the RX 6800 priced $80 above the RTX 3070 ($579 vs. $499).
And please, for the sake of comparison let’s just pretend that we can buy any new tech at MSRP right now. It’s more fun that way.
|PC Perspective GPU Test Platform|
|Processor||AMD Ryzen 9 3900X (1800MHz FCLK)|
|Motherboard||ASUS ROG Crosshair VIII HERO WIFI|
|Memory||HyperX Predator DDR4-3600 CL16 32GB (16GBx2)|
|Storage||Samsung 850 EVO 1TB SSD|
|Power Supply||CORSAIR RM1000x 1000W|
|Operating System||Windows 10 64-bit (Version 1909)|
|Drivers||GeForce Game Ready Driver 452.06 / 456.16 / 456.96
Radeon Software Adrenalin 2020 Edition 20.8.3
Radeon Software Adrenalin 20.45.01.12-11.6 Beta (RX6K)
As always, all benchmark results presented are the average of three separate runs. In the case of any outliers (abnormally low/high results) the game’s results are tossed, and the card re-tested. Every effort is made to provide accurate, repeatable results. With an identical test setup you should see the same numbers, on average, to those presented in the charts to follow.
Note: I didn’t have a Ryzen 5000 processor on hand, so there won’t be any AMD Smart Access Memory feature tests in this review. Sorry!
3DMark Time Spy
We begin with a quick look at graphics scores using both 3DMark Time Spy and Time Spy Extreme. First we have Time Spy, a 2560×1440 DX12 benchmark.
Here we see our first indication that the RTX 3080 Founders Edition will hold a slim overall lead over the RX 6800 XT, but the RX 6800 will offer better performance than RTX 2080 Ti or RTX 3070 Founders Edition cards.
3DMark Time Spy Extreme
Moving up to the 4K test we find a similar result:
Based on Time Spy/Time Spy Extreme it looks like the RTX 3080 FE will be the faster card compared to the 6800 XT, and the RX 6800 will be significantly faster than the RTX 3070. But we must now turn to some game benchmarks to get a clear picture of what you can expect from these cards.
We begin with a game that will favor AMD, and sure enough the first chart has both the RX 6800 XT and RX 6800 beating the RTX 3080 Founders Edition card at 2560×1440. This is a best-case scenario, but we will look at some historically NVIDIA-friendly results as well.
At 3840×2160 (4K) the RX 6800 XT is still far ahead of the RTX 3080 Founders Edition, while the RTX 3080 is in a virtual tie with the RX 6800. If every result looked like this AMD could easily take the gaming graphics crown…
The Division 2
While this game is on the list of AMD optimized titles, we won’t be seeing any DiRT 5-like charts here. Here the RX 6800 XT begins to trade blows with the RTX 3080 Founders Edition.
The cards at the top of the chart stay in the same positions from 2560×1440 to 3840×2160, with the RTX 3080 FE still on top, followed by the RX 6800 XT. Impressively the RX 6800 (non-XT) continues to beat a 2080 Ti FE, which is in turn a bit faster than the RTX 3070 FE.
Metro Exodus is a tough test of any GPU even at the high preset – with ultra and extreme taking things to near Crysis levels. We will stick with “high” for both 2560×1440 and 3840×2160 results.
What’s this? AMD’s RX 6800 XT bests the RTX 3080 FE at 1440/high?! Well, the results are within a single frame per second, so we could call this a tie. Really impressive, regardless. But what about 3840×2160? Won’t the 16GB card have a clear advantage at 4K?
I’m sure there is a scenario in which the available VRAM of an 8GB or 10GB graphics card becomes a bottleneck, but that isn’t Metro Exodus at 4K/high. And I’ll just mention this quickly here: memory allocation does not equal memory usage. Moving on.
Shadow of the Tomb Raider
Another historically NVIDIA-optimized title, Shadow of the Tomb Raider would seem to be a game that could provide an easy win for Team Green. But will that actually be the case?
It’s close, but this is a win for AMD as the RX 6800 XT offered an average of about 2.5 FPS more than the RTX 3080 FE at 1440/high. But when we move up to 4K things change.
Almost the opposite result here at the top of the chart, as NVIDIA’s RTX 3080 FE card edges out the RX 6800 XT by around 2.5 FPS at this higher resolution. The real story here is the RX 6800, which continues to offer outstanding performance – above the level of an RTX 3070 and RTX 2080 Ti.
Far Cry 5
We move back in a time a bit with Far Cry 5, a DX11 title that needs to be run at its highest detail settings to pose much of a challenge for a fast GPU. We tested the game at 4K/ultra here:
The results are very close at the top of the chart, with a very slim victory for the RX 6800 XT that is arguably too close to call at less than 1 FPS. The advantage of the RX 6800 over the 2080 Ti and RTX 3070 is just as impressive in this game. Is it $80 impressive, considering the RX 6800’s $579 launch MSRP? That’s up to you, but it feels like AMD priced these with relative performance in mind (assuming everything is available at MSRP, of course).
GPU Clocks, Power, Temps, and Noise
AMD is pretty much true to the 300W TDP with the RX 6800 XT, with only a few spikes above this with a max reported draw of 326W. Further power testing is planned, with hardware passthrough testing – rather than just software – in the works.
We knew about the power draw, but just look at those frequencies:
GPU clocks spiked as high as 2450 MHz with our RX 6800 XT sample, which is an outrageous number for a stock, air-cooled GPU. (Just think of the possibilities from a liquid-cooled card!)
With the RX 6800 we recorded clocks ranging up to 2250 MHz, and our sample only hit a max of 242W in GPU-Z logging – which is just under the rated 250W TDP.
Next we’ll look at good old fashioned total system power – measured at the wall using a watts up? PRO power meter:
These new cards do pull quite a bit more power than their RX 5700 Series predecessors, but total system draw of 372 W under gaming load from the RX 6800 is still very good for this performance level. The RX 6800 XT draws quite a bit more, but the total system power of 427 W is 35W below our RTX 3080 FE sample.
As to thermals and noise, our initial findings are naturally limited to the AMD reference designs, but these set the bar quite high. We saw outstanding performance, very low noise, and controlled thermals. There was some pesky electrical chatter (choke/coil noise), but not obvious over normal system load noise.
Temps under load with the RX 6800 and 6800 XT were measured in a ~19.5 °C room, with the XT topping out at 77 °C GPU / 97 °C Hot Spot, and the non-XT hitting 77 °C GPU / 90 °C Hot Spot (according to GPU-Z). Clearly our cards were targeting 77 °C, ramping fans and adjusting clocks as needed to maintain this.
Fans reached 50% under load, which resulted in just under 38 dBA with the SPL meter positioned 12 inches from the leading edge of the card in an open case.
I think it’s safe to say that AMD has delivered on the Big Navi promise, and we haven’t even tested BIGGEST Navi yet, the RX 6900 XT. RDNA 2 is a very impressive architecture, to be sure, and the RX 6800 and RX 6800 XT graphics cards are outstanding products. AMD has suddenly and emphatically altered the gaming landscape, bringing us closer to parity than we have been in many years.
AMD now has the performance to compete directly with NVIDIA, and any small disparity in performance with the RX 6800 XT vs. the RTX 3080 was clearly accounted for with the Radeon’s $50 lower MSRP. For its part the RX 6800 seems priced fairly at $579. Beyond raw performance, features (ray tracing, Smart Access Memory, etc.) play a role in the overall story, and we need to wait for mature drivers (and a Ryzen 5000 CPU) to explore all aspects of these new GPUs.
Sadly, this launch will probably end up being another story of limited availability, with 2020 being particularly unkind to enthusiasts looking to upgrade their desktop systems. If we look past availability at what AMD has accomplished here, it’s still worth our highest honor to see the promise of Big Navi fulfilled.
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The GPUs are on loan from AMD for the purpose of this review.
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