I think most of these only scan SAE pids(which are very limited not only in amount of also in frames per second).
A good scanner will scan enhanced pids(also referred to as DMA's or MPID's) which will give MUCH faster frame rates and more detailed information ie knock retard, commanded afr,etc are enhanced pids, without those you are pretty much limited to things like RPM, MPH, etc which most you can see on your dash
