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
Precise rally car control over stages that reward memorisation and tuning.

Execution · Practiced Mastery
A sim racer where driving precision and car tuning both determine lap times.
Dirt 3 leans Execution (Practiced Mastery); Forza Motorsport 4 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.
Dirt 3
Car control on loose surfaces is a high physical ceiling
Forza Motorsport 4
precise braking, throttle, and racing lines
Forza Motorsport 4 leans a little harder on reads, though the gap is small.
Dirt 3
Racing the clock or scripted AI, nobody adapts
Forza Motorsport 4
AI drivers don't meaningfully adapt
Dirt 3 leans a little harder on variance, though the gap is small.
Dirt 3
Surface conditions and minor physics noise per run
Forza Motorsport 4
minor race incident randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt 3
Stage knowledge and setup tuning reward study
Forza Motorsport 4
car tuning and upgrade optimization
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.