AMD Allegedly Shipped Unfinished RDNA 3 ‘Navi 31’ GPU Silicon With Radeon RX 7900 Series Graphics Cards
As discovered by Kepler_L2, it looks like early RDNA 3 silicon had a non-working shader prefetch HW. This was featured in three chips, the GFX1100 (Navi 31), GFX1102 (Navi 33), & GFX1103 (the APU lineup consisting of Phoenix chips). Now based on the latest GitHub submission. Kepler is also suggesting that Navi 32 GPUs are actually based on the ‘GFX1103’ IP whereas Navi 33 chips feature the ‘GFX1102’ IP. The same issues are found on every other chip besides Navi 32 which is going to be featured in several mainstream discrete GPUs on desktop and mobility platforms by early 2023.
— Kepler (@Kepler_L2) December 14, 2022 According to Kepler, this is something that cannot be fixed or revised in a few weeks and will take several months if AMD even plans on fixing this. It would be a major blow if newer silicon with a fix comes out a few months later because the majority of gamers would already have bought the early revision of the Radeon RX 7900 series with the unfinished silicon. What’s likely is that AMD may prepare a refresh a year later that would address these issues but for now, the Radeon RX 7900 series may have to depend massively on driver-level optimizations to address the unfinished GPU nature of their top RDNA 3 silicon. But that’s not all, other major features such as the VOPD instructions featured on the RDNA 3 GPUs claimed to offer a big improvement in performance but in reality, they only managed to deliver a 4 percent improvement over RDNA 2 in ray tracing titles. The RDNA 3 silicon was designed to handle dual Wave32 instructions for twice the floating point performance by utilizing 64 multi-precision & multi-purpose ALUs implemented across 2 SIMD32 units. Talking to an AMD representative, folks over at HardwareTimes were able to confirm that AMD is currently in the process of fine-tuning the performance here and expects optimizations along the way: Reviewers who have also managed to take a first look at various custom AMD Radeon RX 7900 series graphics cards have also reported inconsistent and fluctuating clock speeds on the cards. AMD had also promised up to +54% improvement in power efficiency but that was no where to be seen and the NVIDIA Ada Lovelace architecture blew away RDNA 3 GPUs in all power efficiency metrics on review day. AMD Rep via HardwareTimes
— Nadalina (@NadaOverbeeke) December 14, 2022
Same game, same test run, same settings. Now retesting the XTX, suddenly the same thing: +20% FPS out of nowhere. https://t.co/hvRCPzLqXV — Nadalina (@NadaOverbeeke) December 14, 2022
I don’t think I’ve ever seen such a massive red flag before when it comes to missing power targets. pic.twitter.com/AEGWc424kk — uzzi38 (@uzzi38) December 12, 2022 Just a few days ago, NVIDIA threw shade at AMD & Intel for using their consumers as guinea pigs to BETA test their graphics drivers for them. Now AMD shipping an unfinished silicon also looks like a beta test for their RDNA 3 GPUs that are shipping to gamers across the globe. Following is a breakdown of all the AMD GPU architectures released since Vega: The days ahead for RDNA 3 and especially Radeon RX 7900 series graphics cards based on the Navi 31 GPU silicon will be interesting to see. We have been told by extreme overclockers that they can’t manage to stabilize their cards at higher clock speeds since the silicon is severely limited by power limits and its entirely meaningless to do LN2 OC with the current BIOS.
