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.

Optimization · Pure Optimization
Legendary turn-based strategy of castle economies, hero armies, and tile-perfect logistics.

Optimization · Pure Optimization
Deep empire optimisation over a hidden map against mappable AI.
Heroes of Might and Magic III leans Optimization (Pure Optimization); Sid Meier's Civilization IV 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.
Heroes of Might and Magic III
Turn-based; zero dexterity
Sid Meier's Civilization IV
Turn-based clicks have no physical ceiling
Heroes of Might and Magic III leans a little harder on reads, though the gap is small.
Heroes of Might and Magic III
Human multiplayer adds bluffing; AI is mappable
Sid Meier's Civilization IV
Human multiplayer adds diplomacy reads; AI is mappable
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Heroes of Might and Magic III
Map fog, creature banks, and morale rolls
Sid Meier's Civilization IV
Map generation and unrevealed terrain drive early decisions
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Heroes of Might and Magic III
Hero chains, build orders, and combat math are deeply solvable
Sid Meier's Civilization IV
Tech paths, tile yields and expansion math dominate outcomes
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.