@stonec Physics have definitely edged up a little over the years, main step was the new CPM and tyres with higher number of nodes on them that started a couple of years ago. Not a huge difference, but depending on content (and that includes some stock) I can now encounter out-of-realtime from the occasional CPU spike. But bearing in mind I'm currently on a quad core overclocked to 2.8GHz and DDR2 ram at 800MHz, I think it's fair to say my hardware is reaching the end of its useful life. For rF2.
Dx11 is the nail in the coffin for systems like mine, it drives the processing up just enough to cause much more frequent slow downs.
But I doubt anyone with even 20% better CPU performance would have noticed a change over that time, so it's pretty insignificant.