3DMark is a program with a set of several 3D benchmarks. Fire Strike runs a “heavy” DirectX 11 simulation. Sky Diver also measures DirectX 11 performance, and is aimed on average computers. The Cloud Gate benchmark measures DirectX 10 performance, and the Ice Storm Extreme measures DirectX 9 performance and is targeted to entry-level computers, so we don’t ran it.
Fire Strike ran 7% slower without SMT.
On the Sky Diver benchmark, the Ryzen 7 1700X was 8% slower with SMT disabled.
On the Cloud Gate benchmark, performance drops 20% without SMT.