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

Optimization · Practiced Mastery
Tests class counter knowledge and objective control with lighter economy than classic RTS.

Optimization · Pure Optimization
Large-scale RTS famous for strategic zoom, thousand-unit armies, and a streaming mass-energy economy.
Command & Conquer 4: Tiberian Twilight leans Optimization (Practiced Mastery); Supreme Commander 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.
Command & Conquer 4: Tiberian Twilight
Unit micro and crawler repositioning under pressure
Supreme Commander
Massive APM demands across strategic-zoom battlefields
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Command & Conquer 4: Tiberian Twilight
Class picks and feints against humans reward prediction
Supreme Commander
PvP hinges on scouting and countering opponent commitments
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Command & Conquer 4: Tiberian Twilight
Little hidden beyond fog of war
Supreme Commander
Deterministic engine; only unscouted intel
Supreme Commander leans a little harder on optimization, though the gap is small.
Command & Conquer 4: Tiberian Twilight
Class counters, population caps and objective control are studyable
Supreme Commander
Streaming economy and build-order efficiency are the backbone
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.