Mafia 2 PhysX: Hybrid PhysX

Nvidia locks out using an ATI card with Nvidia PhysX card in its drivers. It claims to do this to ensure compatibility and quality, however there's nothing technically stopping the two working together.

With a bit of Google-fu we found and used Hybrid PhysX mod 1.04ff to modify the PhysX drivers to allow our Radeon HD 5870 1GB to work with a dedicated Nvidia PhysX card. It's impossible to run PhysX on an ATI GPU though, as CUDA is proprietary to Nvidia GPUs.


While the Hybrid PhysX combination isn't perfect it does work and there's just 3fps difference when using both medium and high settings PhysX settings in comparison the GTX 460 768MB. This indicates the GeForce GTX 275 is actually our limitation - not the graphics card. Or is it?

With that in mind we decided to swap things around and use the GTX 460 as our PhysX card.


The result was the same for the HD 5870 1GB (within 1fps). We've thrown in the GTX 275 + GTX 460 PhysX numbers as a comparison - obviously the GTX 275 is slower than the HD 5870 which could account for some performance loss, so maybe it's the CPU holding it back?


Yes! Finally an increase in average frame rate of 10-11fps using both high and medium PhysX detail for an extra 900MHz of CPU versus the numbers above.

We've also included the numbers for the HD 5870 and overclocked CPU to show GPU PhysX is definitely working; without the GTX 460 the performance halves as the CPU takes over PhysX duties.

This is an unofficial setup though - what about doing it the official Nvidia way and going back to our GTX 460 + GTX 275 PhysX card and trying an overclocked CPU?