head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

Execution · Practiced Mastery
A sim racer where driving precision and car tuning both determine lap times.

Execution · Practiced Mastery
Shaving lap time through precise car control and solvable line and tuning choices.
Forza Motorsport 4 leans Execution (Practiced Mastery); Gran Turismo 5 Prologue leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Forza Motorsport 4
precise braking, throttle, and racing lines
Gran Turismo 5 Prologue
Braking points and throttle control decide every lap time
Gran Turismo 5 Prologue leans a little harder on reads, though the gap is small.
Forza Motorsport 4
AI drivers don't meaningfully adapt
Gran Turismo 5 Prologue
Online racecraft adds light wheel-to-wheel prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Forza Motorsport 4
minor race incident randomness
Gran Turismo 5 Prologue
Tracks and physics are fixed and fully knowable
Gran Turismo 5 Prologue leans a little harder on optimization, though the gap is small.
Forza Motorsport 4
car tuning and upgrade optimization
Gran Turismo 5 Prologue
Tuning setups and racing lines are an engineering problem
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.