head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Pure Optimization
The original post-apocalyptic CRPG where character builds solve the wasteland.

Optimization · Pure Optimization
Combat-focused Infinity Engine RPG built on D&D party optimization.
Fallout leans Optimization (Pure Optimization); Icewind Dale leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout
Turn-based, no dexterity
Icewind Dale
Pausable real-time needs little dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout
No adaptive opposition
Icewind Dale
Enemies follow fixed AI scripts
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout
To-hit rolls and random encounters
Icewind Dale
D&D dice rolls and random loot tables
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout
SPECIAL builds and quest routing are deeply solvable
Icewind Dale
Party builds, spell prep, and encounter knowledge
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.