head to head
Fallout: New Vegas asks more than Dawn of Man, and the gap is execution.

Optimization · Pure Optimization
A prehistoric settlement survival builder about guiding a tribe from stone age to iron age.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.
Dawn of Man leans Optimization (Pure Optimization); Fallout: New Vegas leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Dawn of Man
Light real-time camera and command work only.
Fallout: New Vegas
Shooter inputs with VATS assist
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Dawn of Man
Raiders and animals follow scripted, predictable behaviour.
Fallout: New Vegas
Scripted factions and enemies
Dawn of Man leans a little harder on variance, though the gap is small.
Dawn of Man
Raid timing, weather and animal migrations add unknowns.
Fallout: New Vegas
Some loot and crit RNG
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Dawn of Man
Tech progression, food logistics and settlement layout decide survival.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
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.