Even at 1080p using clear conditions we find that Project CARS is very demanding. Most GPUs fall well short of 60fps, with the (previous generation) GTX Titan averaging 59fps.
The GeForce GTX 970 did well, averaging 70fps and putting it just ahead the GTX 780 Ti and matching the GTX 980. Evidently there is a bottleneck limiting performance at around 70fps as the GTX Titan X was only good for 72fps.
Mid-range contenders such as the GTX 770 delivered 50fps, while the GTX 760 only managed 45fps. The GTX 960 delivered a surprising 57fps, making it faster than the GTX 780 which seems unlikely.
Unfortunately for the moment AMD users are limited to ~50fps with the R9 290X, though interestingly the R9 280X wasn't much slower with 42fps. Moreover, the R9 265 was able to beat the GTX 660 with 36fps against 32fps.
Racing in the rain has a significant impact on performance and even high-end GPUs such as the Titan X dropped ~30% of its original performance.
No GPU was able to deliver anywhere near 60fps on the rain with maxed out settings, while none of the affordable mid-range GPUs were able to deliver what we consider to be playable performance. For Project CARS gamers will ideally want a minimum of 30fps and for that a GTX 780 Ti or faster is required.