NVIDIA confirms DLSS Frame Generation does not work on RTX 20/30 GPUs in Portal Prelude RTX, despite what some users claim
We’ve received multiple reports regarding a potential discovery made by gamers in Portal Prelude RTX, a game tech demo jointly released by NVIDIA and Valve, introducing RTX enhancements to the game. Although the original game was launched in 2008, the RTX version has been officially available since July. Given its nature as a tech demo, gamers were quick to experiment with its settings.
Some players have noticed the possible activation of Frame Generation technology on older-generation graphics cards, specifically the RTX 20 and RTX 30 series, which technically lack support for this feature. This finding could be groundbreaking and potentially embarrassing for NVIDIA if they were indeed withholding such a valuable capability from gamers. However, NVIDIA made it clear from the outset that this technology might work on older GPUs, even though it might not deliver an optimal experience, prompting them not to enable it.
In Prelude, the observed frame generation, which can also be monitored using tools like Riva Tuner, does not rely on Optical Flow Frame Generation but rather provides a raw output of new frames. NVIDIA has issued an FAQ to address this issue, including guidance on how to verify if this is indeed the case. The game will produce errors when using NVIDIA Remix tools, indicating the absence of frame generation involvement.
Why does it seem like DLSS Frame Generation works on RTX 20 and 30 series GPUs in Portal Prelude RTX?
A: We’ve noticed that some members of the PC gaming community, like Discord Communities before it, have encountered a bug in an old v18.104.22.168 DLSS DLL that falsely appears to generate frames on 20/30-series hardware. There is no DLSS Frame Generation occurring—just raw duplication of existing frames. Frame counters show a higher FPS, but there is no improvement in smoothness or experience. This can be verified by evaluating the duplicated frames using tools like NVIDIA ICAT, or viewing the error message in the Remix logs indicating an error with frame generation.
DLSS frame generation DLLs have since fixed this bug, and NVIDIA will be issuing an update to RTX Remix in the future to prevent further confusion when frame generation is behaving incorrectly.
Put simply, even though new frames are being produced (technically, this still qualifies as frame generation), it’s crucial to understand that these frames do not benefit from NVIDIA’s DLSS technology. Consequently, they do not provide the level of smoothness and performance that NVIDIA actively promotes with their technology.
NVIDIA has indeed addressed and resolved this bug. However, an update to the game files is still required to prevent this issue from reoccurring and causing further confusion among gamers. Nevertheless, despite the launch of FSR3, it is somewhat disappointing that NVIDIA did not advocate for the idea of enabling this technology, even at a reduced scale, for older GPUs.
Source: NVIDIA Forums