I used to play this game on my crappy 6500 at 1024x768. One of the last games that worked properly on that POS.
Some sources claim that the integrated Intel GPU is on par with a 6600 GT. The main problem with performance on my notebook is that the cooling system is cheap and bad, so that thing actually runs at something like 300 MHz ingame while it's supposed to run at least at 650 MHz. The maximum is supposed to be 1300 MHz; I think at this frequency it could easily give a 6800 Ultra a run for its money.
Even with this limitation, I consider the game playable at 1366x768 and everything (besides the shadows 🙄) on highest. It may sound weird but in such racing games (at least NFSU2/MW) I actually prefer a lower framerate. I think it works way better with the blur effect and therefore gives a better sense of speed. At very high framerates everything looks and feels "cheap", kinda hard to describe without visual representation...