Some of the first batch of Radeon RX 7900 series graphics cards may have been built on structurally unfinished Navi-31 GPUs, as some early buyers of the Radeon RX 7900 XTX and RX 7900 XT have speculated.
AMD’s Navi 31-based Radeon RX 7900 graphics cards with the new RDNA 3 architecture compete with NVIDIA’s GeForce RTX 4080 graphics cards. In independent gaming tests, the older Radeon RX 7900 XTX model was actually faster than the competitor, but only by 4% on average. Some AMD fans are disappointed because the difference is so minor. Furthermore, when it comes to ray tracing games, the new Radeons are still far behind NVIDIA solutions. According to some enthusiasts, the first batch of Radeon RX 7900 XTX and RX 7900 XT graphics cards will be based on GPUs with an early A0 core stepping.
Kepler L2 is a Twitter user. Information discovered in Radeon driver code indicating that hardware shader preloading blocks are disabled programmatically for some Navi GPUs.
Image source: Twitter / @Kepler_L2
This unpleasant feature is common to three chips with the model numbers GFX1100, GFX1102, and GFX1103. The first is the older Navi 31, which serves as the foundation for the Radeon RX 7900 XTX and RX 7900 XT. The second and third are the yet-to-be-released Navi 33 and Navi 32, which will serve as the foundation for AMD’s next-generation desktop and mobile graphics accelerators, including the Radeon RX 7800.
Furthermore, users report strange fluctuations in the operating frequencies of the new Radeon graphics cards. For example, @uzzi38 discovered that the Radeon RX 7900 XTX GPU can run games at frequencies ranging from 2.4 GHz to 2.9 GHz without altering the game settings.
According to TechPowerUp, the difference in frequencies can be even greater. For example, in games, the chip operated at frequencies ranging from 1934 to 2994 MHz, and in the same Furmark stress test, which was supposed to extract all of the juice from the GPU, the GPU frequency was even lower – 1660 MHz.
Image source: TechPowerUp
A similar observation divided Nadalina, a video blogger. In Call of Duty: Modern Warfare 2, she discovered that her ASUS Radeon RX 7900 XT TUF gaming graphics card was operating at 2.4-2.9 GHz with the same quality settings. The card initially selects high GPU frequencies, but after about an hour of gameplay, it drops back to 2.4 GHz, resulting in a 20% performance drop. At the same time, high FPS values are restored after restarting the game. Nadalina’s complaint was noticed by AMD Chief Architect of Gaming Solutions and Marketing Frank Azor, who promised to investigate the matter.
GPU frequency differences under different loads are a fairly common occurrence. The frequency is proportional to the GPU’s load and temperature. However, such a significant difference under similar loads appears strange.
According to the previously mentioned TechPowerUp test, the Radeon RX 7900 XTX consumes 103W of power in standby mode when using multiple monitors, whereas the competition consumes less than 50W. Under such conditions, the GeForce RTX 3090 Ti requires only 42 watts, while the GeForce RTX 4080 and GeForce RTX 4090 require 23 and 27 watts, respectively.
Image source: TechPowerUp
High power consumption issues can be resolved with a new driver, but the same cannot be said for A0’s early stepping. In this case, the only solution is to release a graphics core on a new stepping, which is unlikely to please the first buyers of Radeon RX 7900 series graphics cards. According to some reports, a disabled hardware shader preloader reduces the performance of Radeon graphics cards based on the RDNA 2 architecture by about 5%. It remains to be seen how much its absence will affect the performance of graphics cards based on the RDNA 3 architecture. Now we have to wait for AMD’s official response.
Source: Tech News Space
