Reddit has been slinging some pretty serious accusations at Project CARS developer Slightly Mad Studios recently. A massive post suggests that the PhysX work in the game favours Nvidia cards, and PCs equipped with AMD graphics cards suffer massively. There’s even suggestions that this is a deliberate move because of the studio’s relationship with Nvidia.
Slightly Mad Studios have retaliated today with a press release that denies all the allegations.
“For the past few days, erroneous information posted on Reddit and other websites has spread misinformation with regards to Project CARS’ performance on systems using AMD GPUs,” reads the release. It then goes on to list address a variety of accusations, but key among them is the fact that Slightly Mad worked with both AMD and Nvidia to make the best game possible for both hardware setups.
“Direct involvement with both nVidia and AMD has been fruitful in assisting with the game performance at various stages of development. Both AMD and nVidia have had access to working builds of the game throughout development, and they have both tested builds and reported their results and offered suggestions for performance improvements,” says the release.
“Testing of the game with different driver versions has produced a variety of performance results on both nVidia and AMD hardware. This is entirely to be expected as driver changes cannot always be tested on every game and every card, and this is the reason why both companies produce game-specific driver profiles, to ensure that they can get the best out of the game.”
As for Nvidia-specific technologies, Slightly Mad points out that Project CARS does not use a specific particle technology exclusive to Nvidia, but actually uses a modified version of technology developed for Need for Speed: Shift and Shift Unleashed. That was tech developed in-house by Slightly Mad themselves.
Further points made by the release are:
- Project CARS is not a GameWorks product. We have a good working relationship with nVidia, as we do with AMD, but we have our own render technology which covers everything we need.
- NVidia are not "sponsors" of the project. The company has not received, and would not expect, financial assistance from third party hardware companies.
- The MADNESS engine runs PhysX at only 50Hz and not at 600Hz as mentioned in several articles
- The MADNESS engine uses PhysX for collision detection and dynamic objects, which is a small part of the overall physics systems
- The MADNESS engine does not use PhysX for the SETA tyre model or for the chassis constraint solver (our two most expensive physics sub-systems)
- The MADNESS engine does not use PhysX for the AI systems or for raycasting, we use a bespoke optimised solution for those
- The physics systems run completely independently of the rendering and main game threads and utilises 2 cores at 600Hz
- The physics threading does not interact with the rendering, it is a push system sending updated positional information to the render bridge at 600Hz
- Any performance difference with PhysX would not be reflected with differences in comparing rendering frame rates. There is no interaction between PhysX and the rendering
- Overall, PhysX uses less than 10% of all physics thread CPU on PC. It is a very small part of the physics system so would not make a visual difference if run on the CPU or GPU
Understandably Slightly Mad Studios are upset over the allegations made on Reddit, but this press release certainly cements the studios version of the story. Hopefully it will go a long way to clear up any doubts players have.