Slightly Mad Studios have issued a statement to the press in which they say they feel “compelled” to clear up some misinformation regarding Project Cars, AMD GPUs, and their Madness Engine.
At launch, there seem to have been some driver-related issues with Project Cars and AMD cards (it’s difficult for me to say how extensive this was, as I don’t own the game.) This resulted in some direct contact between Slightly Mad and AMD, as confirmed by the twitter post in our news piece at the time.
Based on a reader comment on that article, it sounded like track textures and grass were causing AMD cards some issues at launch. Whether this is still the case, I don’t know.
Even at the time of the news piece linked above, Slightly Mad were having to refute suggestions that Nvidia had somehow financed a kneecapping of AMD. “Categorically, Nvidia have not paid us a penny. They have though been very forthcoming with support and co-marketing work at their instigation,” wrote Slightly Mad’s Ian Bell in early May.
That sentiment is repeated in this new statement, along with other points clarifying how PhysX is used by the Project Cars Madness Engine, and further points of fact about the driver testing process. Here’s what Slightly Mad have to say:
• 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.
• 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.
• 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.
• Project CARS does not use nVidia specific particle technology – the system we use is a modified version of the same technology we used on the Need for Speed : Shift and Shift Unleashed games, and was entirely developed in-house. The reason the performance drops when there are a lot of particles on screen is simply because processing a large number of particles is very expensive.