AMD Big Navi, Navi 2x, RDNA 2. Whatever you want to call them, AMD's next-generation GPUs are promising big performance and efficiency gains, along with feature parity with Nvidia in terms of ray tracing support. Will Team Red finally take the pole position in our GPU hierarchy and lay claim to the crown for the best graphics card, or will the upcoming Nvidia Ampere architecture — or maybe even Intel Xe Graphics — spoil the party? It's too soon to say, but here's everything we know about Big Navi, including the RDNA 2 architecture, potential performance, expected release date and pricing.
We've done our best to sort fact from fiction, but even without hard numbers from AMD, we have a good idea of what to expect. The recent Xbox Series X and PlayStation 5 hardware announcements certainly add fuel to the fire, and give us realistic ideas of where Big Navi is likely to land in the PC world. If AMD plays its cards right, perhaps Big Navi will finally put AMD's high graphics card power consumption behind it. Let's start at the top, with the new RDNA 2 architecture that powers Big Navi / Navi 2x. But first, here’s a brief list of what we know (or think we know) so far.
Big Navi / RDNA 2 at a Glance
|Specs||Up to 80 CU / 5120 GPU cores|
|Performance||50% better performance per watt|
|Release Date||End of 2020 (if there are no delays)|
|Price||Unknown (but almost certainly higher than RX 5700 XT)|
The RDNA 2 Architecture in Big Navi
Every generation of GPUs is built from a core architecture, and each architecture offers improvements over the previous generation. It's an iterative and additive process that never really ends. AMD's GCN architecture went from first generation for its HD 7000 cards in 2012 up through fifth gen in the Vega and Radeon VII cards in 2017-2019. The RDNA architecture that powers the RX 5000 series of AMD GPUs arrived in mid 2019, bringing major improvements to efficiency and overall performance. RDNA 2 looks to double down on those improvements in late 2020.
First, a quick recap of RDNA 1 is in order. The biggest changes with RDNA 1 over GCN involve a redistribution of resources and a change in how instructions are dispatched. In some ways, RDNA doesn't appear to be all that different from GCN. The instruction set is the same, but how those instructions are dispatched and executed has been improved. RDNA also adds working support for primitive shaders, something present in the Vega GCN architecture that never got turned on due to complications.
Perhaps the most noteworthy update is that the wavefronts — the core unit of work that gets executed — have been changed from being 64 threads wide with four SIMD16 execution units, to being 32 threads wide with a single SIMD32 execution unit. SIMD stands for Single Instruction, Multiple Data; it's a vector processing element that optimizes workloads where the same instruction needs to be run on large chunks of data, which is common in graphics workloads.
This matching of the wavefront size to the SIMD size helps improve efficiency. GCN issued one instruction per wave every four cycles; RDNA issues an instruction every cycle. GCN used a wavefront of 64 threads (work items); RDNA supports 32- and 64-thread wavefronts. GCN has a Compute Unit (CU) with 64 GPU cores, 4 TMUs (Texture Mapping Units) and memory access logic. RDNA implements a new Workgroup Processor (WGP) that consists of two CUs, with each CU still providing the same 64 GPU cores and 4 TMUs plus memory access logic.
How much do these changes matter when it comes to actual performance and efficiency? It's perhaps best illustrated by looking at the Radeon VII, AMD's last GCN GPU, and comparing it with the RX 5700 XT. Radeon VII has 60 CUs, 3840 GPU cores, 16GB of HBM2 memory with 1 TBps of bandwidth, a GPU clock speed of up to 1750 MHz, and a peak performance rating of 13.8 TFLOPS. The RX 5700 XT has 40 CUs, 2560 GPU cores, 8GB of GDDR6 memory with 448 GBps of bandwidth, and clocks at up to 1905 MHz with peak performance of 9.75 TFLOPS.
On paper, Radeon VII looks like it should come out with an easy victory. In practice, across a dozen games that we've tested, the RX 5700 XT is slightly faster at 1080p gaming and slightly slower at 1440p. Only at 4K is the Radeon VII able to manage a 7% lead, helped no doubt by its memory bandwidth. Overall, the Radeon VII only has a 1% performance advantage, but it uses 300W compared to the RX 5700 XT's 225W. In short, AMD is able to deliver roughly the same performance as the previous generation, with a third fewer cores, less than half the memory bandwidth and using 25% less power. That's a very impressive showing, and while TSMC's 7nm FinFET manufacturing process certainly warrants some of the credit (especially in regards to power), the performance uplift is mostly thanks to the RDNA architecture.
That's a lot of RDNA discussion, but it's important because RDNA 2 appears to carry over all of that, with one major new addition: Support for ray tracing. It also supports Variable Rate Shading (VRS), which is part of the DirectX 12 Ultimate spec. There will almost certainly be other tweaks to the architecture, as AMD is making some big claims about Big Navi / RDNA 2 / Navi 2x when it comes to performance per watt. Specifically, AMD says RDNA 2 will offer 50% more performance per watt than RDNA 1, which is frankly a huge jump — the same large jump RDNA 1 saw relative to GCN. It means AMD claims RDNA 2 will deliver either the same performance while using 33% less power, or 50% higher performance with the same power, or most likely some in between solution with higher performance and lower power requirements.
The one thing we know for certain is that RDNA 2 / Big Navi / Navi 2x GPUs will all support hardware ray tracing. That will bring AMD up to feature parity with Nvidia. Note that Nvidia also has Tensor cores in its Turing architecture, which are used for deep learning and AI computations, as well as DLSS (Deep Learning Super Sampling), which has now been generalized with DLSS 2.0 to improve performance and image quality and make it easier for games to implement DLSS. So far, AMD has said nothing about RDNA 2 / Navi 2x including Tensor cores or an equivalent to DLSS, though AMD's CAS (Contrast Aware Sharpening) and RIS (Radeon Image Sharpening) do overlap with DLSS in some ways.
Regarding ray tracing, there was some question as to whether AMD would use the same BVH approach to ray tracing calculations as Nvidia, and with the PlayStation 5 and Xbox Series X announcements out of the way, the answer appears to be yes. If you're not familiar with the term BVH, it stands for Bounding Volume Hierarchy and is used to efficiently find ray and triangle intersections; you can read more about it in our discussion of Nvidia's Turing architecture and its ray tracing algorithm. While AMD didn't provide much detail on its BVH hardware, BVH as a core aspect of ray tracing was definitely mentioned, and we heard similar talk about ray tracing and BVH with the VulkanRT and DirectX 12 Ultimate announcements.
We don't know how much ray tracing hardware is present, or how fast will it be. If AMD takes the same approach as Nvidia and puts one RT core (or whatever AMD wants to call it) into each CU, the comparison between AMD and Nvidia might be easier. However, AMD could mix things up. Instead of one RT unit per CU, maybe it puts two RT cores into each WGP, or four RT cores per WGP, or some other breakdown of computing elements. The fact is, we don't know yet and won't know until AMD says more.
We also know that AMD is planning multiple Navi 2x products, and we expect to see extreme, high-end and mainstream options — though budget Navi 2x seems unlikely, given RX 5500 XT launched this year. AMD could launch multiple GPUs in a relatively short period of time, but more likely we'll see the highest performance options first, followed by high-end and eventually mid-range solutions. Some of those may not happen until 2021, however.
Console Specifications and a Historical Recap
We don't know how many CUs will be present in Navi 2x, for any of the configurations, but there are hints as to what we can expect thanks to the console announcements. We're going to provide a lot of background information on the previous-generation consoles, as well as the upcoming consoles, to help inform our specification speculation. You've been warned.
Xbox Series X will have a relatively-massive 52 CUs in its GPU, while the PlayStation 5 will 'only' have 36 CUs. Sony's PS5 CUs are clocked higher in the PS5, but in terms of raw performance the Xbox Series X is clearly faster. Looking at historical console hardware launches, it's safe to bet that neither represents the pinnacle of what AMD will launch in PC hardware this year.
Back in 2013, when the PlayStation 4 and Xbox One first launched, the PS4 clearly had the faster GPU. It had 18 CUs or 1152 GPU cores running at 800 MHz, compared to the Xbox One with 12 CUs or 768 cores running at 853 MHz. That's 1843 GFLOPS for the PS4 vs. 1310 GFLOPS on the Xbox One. More importantly, though, is the PC graphics hardware AMD was shipping at the time.
The Radeon HD 7970 GHz Edition had been shipping for over a year with 32 CUs and 2048 GPU cores, and up to 4301 GFLOPS. The R9 290X launched around the same time as the PS4 and Xbox One, with 44 CUs and 2816 cores, and the 1050 MHz clock speed meant 5632 GFLOPS. That means AMD's top PC GPU when the PS4 launched was about three times as fast, though the PS4 was closer in terms of memory bandwidth (256 GBps on PS4 vs. 320 GBps on the 290X).
The same thing happened in 2017 with the console updates. PS4 Pro moved to 36 CUs and 2304 cores, with a 911 MHz core clock providing up to 4198 GFLOPS of compute. The Xbox One X had 40 CUs and 2560 cores clocked at 1172 MHz for 6001 GFLOPS. The Xbox is basically using a consolized variant of the RX 580, while the PS4 Pro is using a consolized RX 570. The top PC GPU from AMD in 2017 was RX Vega 64, with 64 CUs and 4096 cores running at up to 1677 MHz, yielding 13,738 GFLOPS of compute. Again, PC hardware was at least twice the compute performance — and since we're comparing similar architectures, it's a 'fair' comparison (ie, unlike comparing GFLOPS between AMD and Nvidia GPUs).
Potential Big Navi / Navi 2x Specifications
What do the console specifications mean for Big Navi / Navi 2x and RDNA 2 desktop GPUs? Obviously times change, but we definitely know a few things. First, AMD is fully capable of building an RDNA 2 / Big Navi GPU with at least 52 CUs, and very likely can go higher. AMD is also using two completely different GPU configurations for the Xbox Series X and PlayStation 5, though that doesn't mean either configuration will actually end up in a PC graphics card. Sony's Mark Cerny was quick to point out that there's some undisclosed 'special sauce' in the PS5 processor, for example. Basically, the upcoming consoles give us a minimum baseline for what AMD can do with Big Navi.
AMD has a lot of options available. The PC Navi 2x GPUs are going to be different from what the consoles are using, because they'll be focused purely on graphics — there's not going to be any Zen 2 CPU chiplet, for example. There's a balancing act between chip size, clock speed and power, and every processor can prioritize things differently. Larger chips use more power and cost more to manufacture, and they typically run at lower clock speeds to compensate. Smaller chips have better yields, cost less and use less power, but for GPUs there's a lot of base functionality that has to be present, so a chip that's half the performance usually isn't half the size.
Looking at Navi 10 and RDNA 1, it's not a stretch to imagine AMD shoving twice the number of GPU cores into a Navi 2x GPU. Navi 10 is relatively small at just 251mm square, and AMD has used much larger die sizes in the past. Anyway, let's cut to the chase. There are lots of rumors floating about, and as always we recommend taking these with a healthy dose of skepticism. The reality is that AMD can and likely will alter CU and core counts as it gets closer to launch. The Navi GPU designs are complete and we've seen a few early demonstrations of working hardware, but that doesn't mean final specs are known — not by AMD, and certainly not by any leakers. A GPU's maximum CU count can't be exceeded, but disabling parts of each GPU is common practice and has been for years.
The following table of potential specs gives a rundown of what we expect to see. The question marks and less than signs indicate our own best guesses based purely on previous GPU launches and the current graphics card market. We've run some numbers to help fill in the remaining data, based on AMD saying Navi 2x / Big Navi / RDNA 2 will provide a 50% improvement in performance per watt compared to Navi 1x. The table gives figures that will deliver on that goal, but AMD can still change TDP, core counts, and clock speeds to end up with the same 50% improvement in performance per watt with completely different specs. We think it's unlikely AMD will go higher than these estimates. Lower is more plausible, and nothing is certain yet.
|GPU||Navi 21 ('Full')||Navi 21 ('Partial')||Navi 23|
|Die size (mm^2)||505||505||?|
|CUs||Up to 80||Up to 64||Up to 40|
|Max Clock (MHz)||<1600||<1800||<2250|
|VRAM Speed (MT/s)||14000||14000||14000|
|Launch Date||Fall 2020||Fall 2020||Winter 2021|
The highest spec rumors point to a Navi 21 GPU with 80 CUs and 5120 GPU cores, basically double the size (505mm square) of the current Navi 10 used in the RX 5700 XT. Those numbers are awfully close to just being double the Navi 10, however, which gives us pause. RDNA 2 has to add new hardware for ray tracing, which judging by Nvidia's Turing GPUs should require quite a few transistors. Let us explain.
The TU106 GPU used in RTX 1060 has a maximum of 36 SMs (Nvidia's equivalent of AMD's CU, basically) and a die size of 445mm square. The TU116 drops the RT and Tensor cores and has a maximum of 24 SMs and a die size of 284mm square. Analyzing die shots of each GPU and focusing just on the SM blocks, we end up with a rough estimate of 5.4mm square for the Turing RTX SM vs. 4.5mm square for the Turing GTX SM — meaning, the RT and Tensor core logic makes each SM about 20% larger. Of course, there's other hardware that doesn't need to be duplicated (eg, video blocks), so twice the CU count of Navi 10 isn't out of the question.
A different rumor gives the same die size and transistor count, but completely different CU and core counts. TechPowerUp lists RX 5900 XT and RX 5900 as having 68 CUs / 4352 cores and 64 CUs / 4096 cores, respectively. (No, we don't think those names are correct — see below.) The core counts are plausible, but the naming seems very unlikely. Still, cutting core counts by 20% means the added ray tracing functionality and other architectural updates could easily fit within the chip. It's also possible this 'smaller' Navi 21 is just the same 80 CU chip but with some of the CUs disabled.
Much less is known about the third potential configuration, Navi 23. There are no leaks discussing die size or transistor counts, which makes sense if AMD plans to ship Navi 21 first and follow up next year with Navi 23. Best guess right now is that Navi 23 ends up being a similar configuration to Navi 10 (ie, 40 CU maximum), but with ray tracing and potentially higher clock speeds. This would be a chip similar to the PlayStation 5's GPU: smaller but with clock speeds well over 2 GHz.
There have been other 'leaks' as well, at least one of which has been explicitly denied. Rumors that Navi 21 would have 24GB of HBM2e and 2 TBps of bandwidth were discounted (strongly) by SK Hynix, for example. Right now, all indications are that Navi 2x will use GDDR6 across all models, though AMD is planning a professional Radeon MI100 part (aka, Arcturus) for the datacenter with 32GB of HBM2, and supposedly only a 200W TDP. That sounds incredibly impressive, though it's not intended for the consumer market. Then again, Radeon VII used a Vega 20 part that was originally intended for the datacenter, so Arcturus could eventually make its way into consumer / prosumer graphics cards.
Let's also point out the recent RX 5600 XT launch, where AMD revealed specs and pricing at CES 2020. Then Nvidia dropped the price of the RTX 2060 to $299 and AMD responded with a last-minute BIOS update that boosted core and memory clocks by about 17%. Except, not every RX 5600 XT card could handle the higher memory clocks. It was a bit of a mess, but the important takeaway is that 'final' specs for Navi 2x are likely nowhere close to being finalized.
Big Navi / Navi 2x Graphics Card Model Names
Another big question is what AMD will call the retail products using Big Navi / Navi 2x GPUs. Navi 10 ended up in RX 5700 XT, RX 5700, and RX 5600 XT. Navi 14 was used in RX 5500 XT. What graphics cards are going to have Navi 2x?
There are two main considerations. First, if Navi 2x delivers 50% more performance per watt than Navi 1x, keeping it in the same GPU family would be extremely confusing, not to mention OEMs and graphics card vendors would love to have a new series of model numbers. Second, AMD has said it will launch a whole series of Navi 2x GPUs.
Given these two facts, even though we don't have RX 5800 or RX 5900 GPUs, we feel it's more likely we'll see RX 6000 or some other change in model name. Again, AMD can go either way, but downplaying the ray tracing abilities in PC graphics cards while the new consoles make a point of adding ray tracing doesn't make much sense.
Big Navi / Navi 2x Release Date
A few months ago, the release date for Navi 2x / RDNA 2 / Big Navi was pretty clear: The first graphics cards using the new GPUs would arrive before the end of 2020. That likely means sometime around October or November, just in time for the holiday shoppers. With the impact of COVID-19 around the globe, a 2020 release date feels less certain, but AMD reiterated that it's still on track to launch the next-gen consoles this year, and that means RDNA 2 GPUs are still likely to make before the holidays (but hopefully sooner).
There has also been talk from TSMC about large order for its 7nm process node from AMD, Nvidia, and others. In fact, TSMC is getting so many orders that rumors are circulating that Nvidia will move some of the lower tier Ampere stuff over to Samsung's 7nm or 8nm nodes. We haven't heard anything about AMD using Samsung, though, and we still expect to see Navi 2x this year.
Big Navi / Navi 2x Cost
We provided our own estimated pricing based on the potential performance and graphics card market in the table near the top. However, AMD officially hasn't said anything in regards to pricing yet. That will remain the case until the final two weeks before launch. Other factors, like the price of competing Nvidia and Intel GPUs, will be considered as the launch date approaches. Let's look back at the Navi 10 / RX 5700 XT launch for context.
Rumors came out more than six months before launch listing various prices. We saw everything from RTX 2080 performance for $250 to $500, or RTX 2060 performance for under $200. AMD officially revealed prices of $449 for the RX 5700 XT and $379 for the RX 5700 about a month before launch. Then Nvidia, to the surprise of pretty much no one, launched its RTX 2070 Super and RTX 2060 Super, providing better performance at lower prices. (The RTX 2080 Super was also announced, but it didn't launch until two weeks after the RX 5700 series.) Just a few days before launch, AMD then dropped the prices of its RX 5700 XT to $399, and the RX 5700 to $349, making them far more appealing. AMD would later go on to state that this was all premeditated — gamesmanship to get Nvidia to reveal its hand early.
The bottom line is that no one — including AMD itself — knows what the actual pricing will be on a new graphics card six months (or more) before launch. There are plans with multiple contingencies, and ultimately the market will help determine the price. If Nvidia launches Ampere before AMD launches Big Navi, that will naturally impact pricing. Intel's Xe Graphics may also prove to be more capable than many are assuming, which would have a knock-on effect to both Ampere and Navi 2x. AMD also explicitly states "enthusiast-class performance" in the above slide, and that has never been synonymous with "affordable."
There are also multiple reports of a 505mm square die size, and if that's correct we have to assume Big Navi / Navi 2x graphics cards will go after the enthusiast segment — meaning, $500 or more. TSMC's 7nm FinFET lithography is more expensive than its 12nm, and 505mm square means yield and dies per wafer are both going to be higher. Plus, 12GB of GDDR6 will increase both the memory and board price. Big chips lead to big prices, in other words.
The only real advice we can give right now is to wait and see. AMD (and Nvidia and Intel) will do its best to deliver RDNA 2 and Navi 2x GPUs at compelling prices. That doesn't mean we'll get RTX 2080 Super performance for $250, sadly, but if Big Navi can give Nvidia some much-needed competition in the enthusiast graphics card segment, we should see bang-for-the-buck improvements across the entire spectrum of GPUs. And if AMD really does have an 80-CU monster Navi 21 GPU coming that will beat the RTX 2080 Ti in performance, we expect it to charge accordingly.