  The S66 benchmark for noncovalent interactions has been re-evaluated using
explicitly correlated methods with basis sets near the one-particle basis set
limit. It is found that post-MP2 "high-level corrections" are treated
adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis
sets on the one hand, and (T) extrapolated from conventional
CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier
benchmarks on the larger S66x8 problem set in particular, and for accurate
calculations on noncovalent interactions in general, are discussed. At a slight
cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+
basis sets, while half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best
compromise between accuracy and computational cost.
