  By using a single formalism to handle charm, strange and light valence quarks
in full lattice QCD for the first time, we are able to determine ratios of
quark masses to 1%. For $m_c/m_s$ we obtain 11.85(16), an order of magnitude
more precise than the current PDG average. Combined with 1% determinations of
the charm quark mass now possible this gives $\bar{m}_s(2{\rm GeV}) =$
92.4(1.5) MeV. The MILC result for $m_s/m_l = 27.2(3) $ yields $\bar{m}_l(2{\rm
GeV})$ = 3.40(7) MeV for the average of $u$ and $d$ quark masses.
