  We propose an all orders beta function for ordinary Yang-Mills theories with
or without fermions inspired by the Novikov-Shifman-Vainshtein-Zakharov beta
function of N=1 supersymmetric gauge theories. The beta function allows us to
bound the conformal window. When restricting to one adjoint Weyl fermion we
show how the proposed beta function matches the one of supersymmetric
Yang-Mills theory. The running of the pure Yang-Mills coupling is computed and
the deviation from the two loop result is presented. We then compare the
deviation with the one obtained from lattice data also with respect to the two
loop running.
