  We discuss the Hard Dense Loop resummation at finite quark mass and evaluate
the equation of state (EoS) of cold and dense QCD matter in $\beta$
equilibrium. The resummation in the quark sector has an effect of lowering the
baryon number density and the EoS turns out to have much smaller uncertainty
than the perturbative QCD estimate. Our numerical results favor smooth matching
between the EoS from the resummed QCD calculation at high density and the
extrapolated EoS from the nuclear matter density region. We also point out that
the speed of sound in our EoS slightly exceeds the conformal limit.
