"For the considered single-depot case, the problem can be formulated as a large-scale minimum-cost flow problem that we solve with a network simplex algorithm accelerated with a column generation. The core of the benchmark 181.mcf is the network simplex code 'MCF Version 1.2 -- A network simplex implementation', For this benchmark, MCF is embedded in the column generation process." http://www.spec.org/cpu2000/CINT2000/181.mcf/docs/181.mcf...
In any case, if 181.mcf is so poorly written, perhaps someone could do us the favor of benchmarking other pointer intensive code instead of dismissing x32 without bothering to conduct a single relevant benchmark.