head to head
S.T.A.L.K.E.R.: Call of Pripyat asks more than Grand Theft Auto: San Andreas, and the gap is variance.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.

Optimization · Practiced Mastery
The most polished S.T.A.L.K.E.R., a freeform survival shooter around Pripyat.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); S.T.A.L.K.E.R.: Call of Pripyat leans Optimization (Practiced Mastery).
S.T.A.L.K.E.R.: Call of Pripyat leans a little harder on execution, though the gap is small.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
S.T.A.L.K.E.R.: Call of Pripyat
Deliberate gunplay against mutants and stalkers
S.T.A.L.K.E.R.: Call of Pripyat leans a little harder on reads, though the gap is small.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
S.T.A.L.K.E.R.: Call of Pripyat
A-Life simulation doesn't counter-adapt to you
S.T.A.L.K.E.R.: Call of Pripyat leans clearly harder on variance.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
S.T.A.L.K.E.R.: Call of Pripyat
Emissions, artifact spawns, and mutant encounters are random
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
S.T.A.L.K.E.R.: Call of Pripyat
Detector use, upgrades, and quest routing converge
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.