If you can change the number of things it polls, then if its running over OBDII then the less things you have it should speed it up significantly. Say you can get it to poll 10 things at once or just revs, if you have revs showing in both cases, in one the refresh of revs should be a lot quicker than the other. The reason for this is the OBD isnt designed for fast refresh and there is only a certain number of things the OBD can report at once. So say it can poll something ever 1/10th of a second, if you have 10 things running, it can only poll each every second. If you have one it can poll it every 1/10th second. If that makes sense? If it doesnt speed up or slow down the response then likley its over CANBUS which is designed (from what I've read) to handle the polling quicker.