I've still got loads of stuttering on my laptop as well, but I seem to have identified the cause on my end: Setting PhysX to CPU helped a lot, but the main culprit was actually the sound!
Whenever a stutter was about to occur, the sound always went away first. It got quiet, and then came the stutter (usually in the form of the screen freezing for up to 5 seconds), and then when it's over the sound is back.
So I disabled all music and sound effects, and the stutters ceased entirely.
Could it be an issue with the audio engine? The graphics card I've got is perfectly able to run the game on Ultra at a stable 60 FPS (except in stations), and the stutters do strike me as the kind of stutters you get when the CPU is struggling with something.
Edit: Another thing I've noticed is the stutters and audio issues increase in frequency with other players in the space around me, even in normal and hyperspace.