A few days ago, it came to light that Nvidia has dropped support for 32-bit CUDA applications with its latest RTX 50-series (Blackwell) GPUs. Support for PhysX has gradually faded over the years. However, PhysX can still be offloaded to an RTX 40-series (Ada Lovelace) or older GPU, and that's exactly what a user at Reddit has done. In addition, we've gathered some interesting benchmarks, courtesy of VerbalSilence on YouTube and the same Reddit user, where the GTX 980 Ti handily outperforms the RTX 5090 in 32-bit PhysX games.
PhysX is fully functional in 64-bit applications like Batman: Arkham Knight, so Nvidia hasn't abandoned the technology entirely. However, the GPU maker has retired 32-bit CUDA support for RTX 50-series GPUs (and likely beyond). Given the age of the technology, most games with PhysX were compiled using 32-bit CUDA libraries. This is a software limitation, for the most part, though maintaining support for legacy environments is easier said than done.
As the news dropped, a Redditor snagged a separate RTX 3050 GPU to pair with the primary RTX 5090 to maintain PhysX support in older 32-bit titles. Using the Nvidia Control Panel, you can offload PhysX computations to a separate GPU or CPU, which you never need to do. Around 20 years back, dedicated processors for computing physics calculations were dubbed PPUs (Physics Processing Units). Ageia used to make such devices, which Nvidia later acquired.
Game | RTX 5090 with RTX 3050 | RTX 5090 |
|---|---|---|
Mafia II Classic | 157.1 | 28.8 |
Batman Arkham Asylum | 390 | 61 |
Borderlands 2 | 122 | N/A |
Assassin's Creed IV: Black Flag | 62 | 62 |
In older 32-bit titles, there's a substantial gap between using the RTX 3050 and without. With legacy PhysX no longer supported, RTX 50 GPUs crash when you enable the setting or fall back to CPU processing. The user mentions that despite setting the RTX 3050 as a dedicated PhysX processor, 64-bit games utilize the RTX 5090 anyway. As mentioned above, modern PhysX implementations, at least the handful that exist, should still run fine on Blackwell.
Another test conducted by VerbalSilence reveals a striking difference in Mirror's Edge, where in some scenes, the RTX 5080 plummets to less than 10 FPS while the GTX 980 Ti sits comfortably at almost 150 FPS. The performance delta is heavily dependent on the game's PhysX implementation. Still, Borderlands 2 sees the GTX 980 Ti lead the RTX 5080 by almost 2X, and that's telling. Here, the GTX 980 Ti system is coupled with a Core i5-4690K, with the Ryzen 7 9800X3D reserved for the RTX 5080 setup.
It's unlikely that Nvidia will reinstate compatibility for legacy CUDA applications. If you genuinely wish to play your favorite 32-bit titles with PhysX, maybe it's time to dust off that old GPU in your cabinet and restore it to service.
