AMD Big Navi specs just leaked — and the RTX 3080 could be in trouble

AMD Big Navi
(Image credit: Shutterstock)

AMD Big Navi could be twice as powerful as the Radeon RX 5700 XT, making it a graphics card that could be a serious rival to the rumored Nvidia GeForce RTX 3080.

The Big Navi GPU — now thought to be codenamed Sienna Cichlid — will apparently have 80 compute units (CUs) in its top-end configuration, according to tech leaker Rogame. It was previously thought Big Navi would have 72CUs split into two 36CU clusters. 

But in its maximum configuration, Big Navi could have double the CUs of the RX 5700 XT’s 40 CUs. The latter graphics card is the most powerful AMD GPU you can currently buy and it’s a Navi card that makes use of AMD’s latest RDNA GPU architecture. 

But Big Navi is set to use RDNA 2 GPU architecture, the same as the GPUs in the PS5 and Xbox Series X, and promises to deliver more performance-per-watt than the previous generation RDNA. Given the Radeon RX 5700 XT was no slouch — roughly comparable to a GeForce RTX 2070 — we’d expect big things from Big Navi.

Rogame tweeted a table that showed some of the specs of Big Navi, thought to be referred to as Navi 21 inside AMD. It revealed the upcoming GPU will have four shader engines and two shader arrays per shader engine, with 10CUs per shader array. When all added up, that gives 80CUs. 

According to WCCFtech, 80CUs translates to 5,120 stream processors, which if AMD is able to run Big Navi at a clock speed of around 1,700MHz, then Big Navi could deliver 17.5 teraflops per second of compute power by itself. When combined with a powerful CPU, we’d expect Big Navi to then deliver a very powerful gaming PC.

The leaks thus far have suggested Big Navi will be 40% to 50% more powerful than an Nvidia GeForce 2080 Ti, the most powerful consumer graphics card currently available. And it could also beat the GeForce RTX 3080, which is expected to be revealed sometime between August and October.

However, these specs and predicted power will need to translate into real-world gaming performance. That can often be down to GPU drivers and compatibility, as well as other optimizations. So Big Navi looks good on paper, but it will still have to deliver the promised performance in real-world tests when it arrives; it’s predicted to pop up between September and November.

It’s also worth noting that this listing for Navi 21 could actually refer to other upcoming GPUs from AMD, perhaps aimed to sit above the RX 5700 but not quite chase the top-end Nvidia cards. One of these cards could be the Radeon RX 5800 for example.

That could then mean Big Navi will be even more powerful. But with no official word from AMD, all we have is speculation.

Regardless, going on these leaks and other rumours, Big Navi is set to be an impressive graphics card. And it will need to be, given Nvidia will bring in new GeForce graphics cards based on its new Ampere GPU architecture, which promises boosted performance across the board as well as improved ray-tracing.

Roland Moore-Colyer

Roland Moore-Colyer a Managing Editor at Tom’s Guide with a focus on news, features and opinion articles. He often writes about gaming, phones, laptops and other bits of hardware; he’s also got an interest in cars. When not at his desk Roland can be found wandering around London, often with a look of curiosity on his face.