We're trying to figure this out, and after further testing with Saso, I found the C172 (my small, default aircraft of choice) and the 747 (my large, default aircraft of choice), both have identical spikes and stuttering to the TBM. I'm not really certain why the default C172 is not giving you stuttering, but see my images below of each aircraft. Just an FYI, I'm aware of the locking at 30fps reason. But for me, I obviously don't place as much importance on it as you may. Different strokes for different folks, I guess.
I'll leave this to Saso to continue to diagnose, because this seems like a sim issue to me.
TBM
Default C172
Default 747