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

Execution · Pure Mechanics
One of the most mechanically demanding racers ever made, where mastering its physics tech is everything.

Execution · Pure Mechanics
High-speed trick execution along optimised lines down fixed mountains.
F-Zero GX leans Execution (Pure Mechanics); SSX leans Execution (Pure Mechanics).
F-Zero GX leans a little harder on execution, though the gap is small.
F-Zero GX
Snaking and frame-tight control at absurd speeds
SSX
Trick timing, landings and line control at speed are everything
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
F-Zero GX
No adaptive opposition
SSX
Rival AI racers are aggressive but mappable
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
F-Zero GX
Fixed tracks, deterministic physics
SSX
Courses are fixed once learned
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
F-Zero GX
Machine settings and advanced technique routes are mappable
SSX
Optimal trick lines and shortcut routing maximise score
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.