head to head
Gran Turismo 3: A-Spec asks more than Grand Theft Auto: San Andreas, and the gap is execution.

Execution · Practiced Mastery
A PS2 driving simulator centred on mastering tracks and tuning cars through events.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.
Gran Turismo 3: A-Spec leans Execution (Practiced Mastery); Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery).
Gran Turismo 3: A-Spec leans clearly harder on execution.
Gran Turismo 3: A-Spec
Lap precision against the clock is the core test
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Gran Turismo 3: A-Spec
AI opponents never adapt
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Grand Theft Auto: San Andreas leans a little harder on variance, though the gap is small.
Gran Turismo 3: A-Spec
Deterministic physics, minimal randomness
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Gran Turismo 3: A-Spec leans a little harder on optimization, though the gap is small.
Gran Turismo 3: A-Spec
Optimal cars, tunes, and racing lines are findable
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.