Diffusion fMRI (dfMRI) is an alternative to BOLD fMRI. Here, we present the first dfMRI study in humans attempting to minimize all sources of BOLD contamination and comparing functional responses at two field strengths, both for task and resting-state fMRI. Our study benefits from unprecedented high spatiotemporal resolution. We observed task-induced water diffusivity decreases in the perfusion-free b-value regime. Furthermore, we found that positive correlations were largely preserved while anti-correlations were suppressed in dfMRI functional connectivity compared to BOLD. We conclude that dfMRI contrast is genuine and distinct from BOLD mechanisms.