Speedups of the OpenMP-parallelised FCFC with respect to the serial version on Haswell and Knights Landing CPUs with different numbers of OpenMP threads, measured using a periodic cubic random catalogue with Ν = 5 × 10⁷, L_box = 3 h⁻¹ Gpc, and with 200 linear s bins in [0, 200) h⁻¹ Mpc and 120 μ bins in [0, 1). The dashed line denotes the theoretical maximum speedup. SIMD is enabled in all cases.