  We explore the variability properties of long, high cadence GRMHD simulations
across the electromagnetic spectrum using an efficient, GPU-based radiative
transfer algorithm. We focus on both disk- and jet-dominated simulations with
parameters that successfully reproduce the time-averaged spectral properties of
Sgr A* and the size of its image at 1.3mm. We find that the disk-dominated
models produce short timescale variability with amplitudes and power spectra
that closely resemble those inferred observationally. In contrast,
jet-dominated models generate only slow variability, at lower flux levels.
Neither set of models show any X-ray flares, which most likely indicate that
additional physics, such as particle acceleration mechanisms, need to be
incorporated into the GRMHD simulations to account for them. The disk-dominated
models show strong, short-lived mm/IR flares, with short (<~ 1hr) time lags
between the mm and IR wavelengths, that arise from strong-field gravitational
lensing of magnetic flux tubes near the horizon. Such events provide a natural
explanation for the observed IR flares with no X-ray counterparts.
