That's the advantage of the consoles, the developers have a well known and consistent platform. With PC's the end users can configure, tweak, build, install, replace, remove, hardware and software components to their heart's content with no quality control. Some problems can be directly related to the developers creation but pin-pointing the other problems can be hard - what works for one may not work for another (but then very rarely comparing red apples to red apples).
There was another post within the last day or so from a R3E/DTM poster that is having problems getting that game to perform well but claims no issues with any other. This thread is problems with GSCE but not with any others... hmmm.
Last night I ran DTM, AC, and GSCE with similar conditions - starting at the back of a 22 car field and using vSync (I use vSync). They all performed similarly. At the start, AC was the worse (40 FPS) for a short period of time but came up to a steady 60 FPS level pretty quickly. R3E/DTM at the start was 50-55 stayed there for part lap then locked at 60 for the rest of race. GSCE started and stayed locked at 60 FPS but dipped to 40 for very brief periods of time when a lot of dust and smoke was kicked up. All were very playable. I am running triples at 5816x1080 with a single GTX780. I could get all to never drop below 60 FPS if I lower some settings but it isn't worth it to me for the brief and playable dips.
I also run pCARS and others, which for me run similarly but depending on variables.
Your mileage may vary but these PC games take tweaking that many don't have the patience for. If it was always the games fault, no one would be having success. If it isn't worth the trouble, then an option is to avoid the games causing issues. All of the above are too good to avoid for me.