The internet is alive with rumors about the cryptocurrency mining prowess of AMD’s new RDNA 2 architecture, as seen in the new Radeon RX 6800, 6800 XT and 6900 XT GPUs. According to a user on QQ, a snapchat-like social media platform in China, the vanilla RX 6800 is completely 1.5 faster than Nvidia’s powerful GeForce RTX 3090.
If accurate, it would make the 6800 and implicitly all AMD RDNA 2 cards considerably more efficient for crypto mining than Nvidia’s Ampere GPUs. This would also imply a huge struggle between miners competing to buy RDNA 2 cards and, in turn, inflated prices and run based on availability. Isn’t that cool if you’re thinking of buying one of these playing cards for, you know, games.
After all, we’ve already been there in 2017 and 2018, when the retail prices of many graphics were double the recommended prices thanks to mining demand. In fact, mining is at least partly to blame for how the MSRP price of all GPUs has also risen over the past four or five years.
But is the rumor about RDNA 2 muscle mining really true? On balance, probably not. Aside from the fact that the source is hardly the last word in verified authority, the workload for most cryptocurrencies is bandwidth sensitive. This appears to be a notable weakness of all new RDNA 2 GPUs thanks to their relatively narrow 256-bit memory buses.
There is likely room for RDNA 2 to work well if the bandwidth-sensitive portions of the mining workload can fit into AMD’s 128MB Infinity Cache, a feature designed to reduce the need to retrieve data from VRAM. on that 256-bit bus. However, for example, the current Ethereum DAG file is around 4GB. To avoid VRAM polling during Ethereum hashing, therefore, RDNA 2 would need a 4GB on-chip cache.
However, many currencies are specifically designed to avoid being accelerated by cache hits. Plus, it’s AMD’s CDNA architecture that we’d expect to be the mining beast. RDNA and RDNA 2, in general, were designed to be a rendering and rasterizing monster, not a processing beast.
In fact, if one were going to design a GPU architecture that was fast for gaming but not so much mining, it would look a lot like RDNA 2 with its modest 256-bit Infinity plus cache technology and conventional drive ratios. calculation, texture processing and pixel output.
However, it will certainly be an interesting issue to monitor as RDNA 2 cards will be released later this month. If it turns out that Nvidia’s Ampere-based RTX 3000 series cards are the weapon of choice for cryptocurrency mining, that will only worsen Nvidia’s supply and price issues further. Look at this space.