  High precision radial velocity (RV) measurements have been central in the
study of exoplanets during the last two decades, from the early discovery of
hot Jupiters, to the recent mass measurements of Earth-sized planets uncovered
by transit surveys. While optical radial-velocity is now a mature field, there
is currently a strong effort to push the technique into the near-infrared (nIR)
domain (chiefly $Y$, $J$, $H$ and $K$ band passes) to probe planetary systems
around late-type stars. The combined lower mass and luminosity of M dwarfs
leads to an increased reflex RV signal for planets in the habitable zone
compared to Sun-like stars. The estimates on the detectability of planets rely
on various instrumental characteristics, but also on a prior knowledge of the
stellar spectrum. While the overall properties of M dwarf spectra have been
extensively tested against observations, the same is not true for their
detailed line profiles, which leads to significant uncertainties when
converting a given signal-to-noise ratio to a corresponding RV precision as
attainable on a given spectrograph. By combining archival CRIRES and HARPS data
with ESPaDOnS data of Barnard's star, we show that state-of-the-art atmosphere
models over-predict the $Y$ and $J$-band RV content by more than a factor of
$\sim$$2$, while under-predicting the $H$ and $K$-band content by half.
