The dose and the purity is what makes all the difference here. When someone takes Adderall orally, they are taking racemic amphetamine and dextroamphetamine at a dose typically around 10-20mg per day. When someone smokes pure d-methamphetamine, they are typically smoking 50-70mg in one or two large hits. Now, I do not condone or suggest this, but imagine taking 50-60mg of instant Adderall in the morning.

I think the comparison you want to look at is Adderall vs. methamphetamine. Incidentally, addicts can't tell the difference between the two drugs if ingested in pill form at the same relative dosage. This is comparable to how opiate addiction works; an addict can't tell the difference between morphine and heroin, it just takes twice as much morphine to get the same effect.