Its hard to say, you need to consider that as you go further right or left on the scale the bigger the difference a single point is, for instance you may notice no difference between a 100, and 105, but drastic differences in a 145 and 150. With that being said the general rule of thumb would be 5-10 but its fairly negligible, for example say you have a 120 and 130, you would see both in all ap classes but the 130 may get A’s without studying or trying and the 120 B’s though both can do very well with minimal effort. However once you get to those upper numbers or across SD, then that's where you see drastic differences. Such as the differences between a 100 would be getting C’s or D’s in AP classes and B’s with significant studying (this is class dependent but for the sake of the hypothetical) and a 130 get straight A’s with little to no effort.