  Thermodynamic uncertainty relations (TURs) set fundamental bounds on the
fluctuation and dissipation of stochastic systems. Here, we examine these
bounds, in experiment and theory, by exploring the entire phase space of a
cyclic information engine operating in a non-equilibrium steady state. Close to
its maximal efficiency, we find that the engine violates the original TUR. This
first experimental demonstration of TUR violation agrees with recently proposed
softer bounds: The engine satisfies two generalized TUR bounds derived from the
detailed fluctuation theorem with feedback control and another bound linking
fluctuation and dissipation to mutual information and Renyi divergence. We
examine how the interplay of work fluctuation and dissipation shapes the
information conversion efficiency of the engine, and find that dissipation is
minimal at a finite noise level, where the original TUR is violated.
